Killer Wi-Fi 6 AX1650i WiFi Slow Connections on 5.11 Kernel

Question

seems like a very, common & frustrating topic... but my wifi is at a super slow crawl. I am getting speeds slower than dial-up modems, which gets maddening when you are trying develop a website.

TEMPORARY SOLUTION After trying -EVERY- solution below, nothing worked. So I used Timeshift and rolled back my machine to Oct. 22nd, then I did NOT do any updates or upgrades.. and now wifi seems to be working pretty well. So I plan to ignore updates & upgrades for the next month and see if the problem gets corrected elsewhere. It was definitely a recent update that caused this problem.

This is my hardware:

$sudo lshw -class network -short && nmcli device status 
H/W path             Device          Class          Description
===============================================================
/0/100/14.3          wlp0s20f3       network        Killer Wi-Fi 6 AX1650i 160MHz Wireless Network Adapter

My current kernel is: 5.11.0-38-generic

More Details
$ lsb_release -a

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.3 LTS
Release:    20.04
Codename:   focal

I have tried -all- of the solutions found here: Ubuntu 20.04 Network Performance Extremely Slow and nothing has worked.

Does anybody have any new tricks, that I can try? even 1MB download would be a blessing from the heavens.

Additional Requested Info

Machine Brand/Model: Acer Aspire 5 A515-55G

Command 1:

$ sudo lshw -class network
[sudo] password for dragonpharaoh: 
  *-network                 
       description: Wireless interface
       product: Killer Wi-Fi 6 AX1650i 160MHz Wireless Network Adapter (201NGW)
       vendor: Intel Corporation
       physical id: 14.3
       bus info: pci@0000:00:14.3
       logical name: wlp0s20f3
       version: 30
       serial: 34:cf:f6:61:c0:38
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=5.11.0-38-generic firmware=59.601f3a66.0 Qu-c0-hr-b0-59.uc ip=192.168.0.20 latency=0 link=yes multicast=yes wireless=IEEE 802.11
       resources: iomemory:600-5ff irq:16 memory:6013104000-6013107fff
  *-network
       description: Ethernet interface
       product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: enp3s0
       version: 15
       serial: b4:a9:fc:b0:b0:d1
       capacity: 1Gbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=5.11.0-38-generic firmware=rtl8168h-2_0.0.2 02/26/15 latency=0 link=no multicast=yes port=twisted pair
       resources: irq:16 ioport:4000(size=256) memory:51104000-51104fff memory:51100000-51103fff

Command 2:

$ ls -al /etc/pm/config.d/
ls: cannot access '/etc/pm/config.d/': No such file or directory

Command 3:

$ ls -al /etc/modprobe.d/
total 64
drwxr-xr-x   2 root root  4096 Sep 20 17:55 .
drwxr-xr-x 177 root root 12288 Oct 29  2021 ..
-rw-r--r--   1 root root  2507 Jul 31  2015 alsa-base.conf
-rw-r--r--   1 root root   154 Feb 16  2020 amd64-microcode-blacklist.conf
-rw-r--r--   1 root root   325 Mar 12  2020 blacklist-ath_pci.conf
-rw-r--r--   1 root root  1518 Mar 12  2020 blacklist.conf
-rw-r--r--   1 root root   210 Mar 12  2020 blacklist-firewire.conf
-rw-r--r--   1 root root   677 Mar 12  2020 blacklist-framebuffer.conf
-rw-r--r--   1 root root   156 Jul 31  2015 blacklist-modem.conf
lrwxrwxrwx   1 root root    41 Dec 28  2020 blacklist-oss.conf -> /lib/linux-sound-base/noOSS.modprobe.conf
-rw-r--r--   1 root root   583 Mar 12  2020 blacklist-rare-network.conf
-rw-r--r--   1 root root   127 Jan 22  2020 dkms.conf
-rw-r--r--   1 root root   154 Jun 11  2020 intel-microcode-blacklist.conf
-rw-r--r--   1 root root   347 Mar 12  2020 iwlwifi.conf
-rw-r--r--   1 root root    95 Sep 20 17:55 v4l2loopback.conf

Command 3:

$ lspci -knn | grep Net -A2
00:14.3 Network controller [0280]: Intel Corporation Killer Wi-Fi 6 AX1650i 160MHz Wireless Network Adapter (201NGW) [8086:34f0] (rev 30)
    Subsystem: Intel Corporation Killer Wi-Fi 6 AX1650i 160MHz Wireless Network Adapter (201NGW) [8086:0074]
    Kernel driver in use: iwlwifi
    Kernel modules: iwlwifi

Command 4:

   $ modinfo iwlwifi
Too long, pastebin:
https://pastebin.com/ThKWTSyf

Command 5:

$ sudo iwlist freq
lo        no frequency information.
enp3s0    no frequency information.
wlp0s20f3  32 channels in total; available frequencies :
          Channel 01 : 2.412 GHz
          Channel 02 : 2.417 GHz
          Channel 03 : 2.422 GHz
          Channel 04 : 2.427 GHz
          Channel 05 : 2.432 GHz
          Channel 06 : 2.437 GHz
          Channel 07 : 2.442 GHz
          Channel 08 : 2.447 GHz
          Channel 09 : 2.452 GHz
          Channel 10 : 2.457 GHz
          Channel 11 : 2.462 GHz
          Channel 12 : 2.467 GHz
          Channel 13 : 2.472 GHz
          Channel 36 : 5.18 GHz
          Channel 40 : 5.2 GHz
          Channel 44 : 5.22 GHz
          Channel 48 : 5.24 GHz
          Channel 52 : 5.26 GHz
          Channel 56 : 5.28 GHz
          Channel 60 : 5.3 GHz
          Channel 64 : 5.32 GHz
          Channel 100 : 5.5 GHz
          Channel 104 : 5.52 GHz
          Channel 108 : 5.54 GHz
          Channel 112 : 5.56 GHz
          Channel 116 : 5.58 GHz
          Channel 120 : 5.6 GHz
          Channel 124 : 5.62 GHz
          Channel 128 : 5.64 GHz
          Channel 132 : 5.66 GHz
          Channel 136 : 5.68 GHz
          Channel 140 : 5.7 GHz
          Current Frequency:2.412 GHz (Channel 1)
wg-client1  no frequency information.
vboxnet0  no frequency information.

Command 6:

$ sudo iwconfig
lo        no wireless extensions.
enp3s0    no wireless extensions.
wlp0s20f3  IEEE 802.11  ESSID:"8D"

          Mode:Managed  Frequency:2.412 GHz  Access Point: 1C:AB:C0:21:E1:C8

          Bit Rate=144.4 Mb/s   Tx-Power=22 dBm

          Retry short limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=70/70  Signal level=-31 dBm

          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:900   Missed beacon:0
wg-client1  no wireless extensions.
vboxnet0  no wireless extensions.

Command 7:

$ inxi -Fxz
System:    Kernel: 5.11.0-38-generic x86_64 bits: 64 compiler: N/A Desktop: Gnome 3.36.9 
           Distro: Ubuntu 20.04.3 LTS (Focal Fossa) 
Machine:   Type: Laptop System: Acer product: Aspire A515-55G v: V1.13 serial: <filter> 
           Mobo: IL model: Doc_IL v: V1.13 serial: <filter> UEFI: Insyde v: 1.13 date: 10/15/2020 
Battery:   ID-1: BAT1 charge: 39.5 Wh condition: 39.5/53.0 Wh (75%) model: PANASONIC AP19B5L status: Full 
CPU:       Topology: Quad Core model: Intel Core i5-1035G1 bits: 64 type: MT MCP arch: Ice Lake rev: 5 L2 cache: 6144 KiB 
           flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 19046 
           Speed: 2256 MHz min/max: 400/3600 MHz Core speeds (MHz): 1: 2995 2: 3104 3: 3389 4: 3109 5: 2424 6: 1099 7: 3223 
           8: 3275 
Graphics:  Device-1: Intel vendor: Acer Incorporated ALI driver: i915 v: kernel bus ID: 00:02.0 
           Device-2: NVIDIA GP107M [GeForce MX350] vendor: Acer Incorporated ALI driver: nvidia v: 460.91.03 bus ID: 02:00.0 
           Display: x11 server: X.Org 1.20.11 driver: modesetting,nvidia unloaded: fbdev,nouveau,vesa 
           resolution: 1920x1080~60Hz 
           OpenGL: renderer: GeForce MX350/PCIe/SSE2 v: 4.6.0 NVIDIA 460.91.03 direct render: Yes 
Audio:     Device-1: Intel Smart Sound Audio vendor: Acer Incorporated ALI driver: snd_hda_intel v: kernel bus ID: 00:1f.3 
           Sound Server: ALSA v: k5.11.0-38-generic 
Network:   Device-1: Intel Killer Wi-Fi 6 AX1650i 160MHz Wireless Network Adapter driver: iwlwifi v: kernel port: 6000 
           bus ID: 00:14.3 
           IF: wlp0s20f3 state: up mac: <filter> 
           Device-2: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: Acer Incorporated ALI driver: r8169 
           v: kernel port: 4000 bus ID: 03:00.0 
           IF: enp3s0 state: down mac: <filter> 
           IF-ID-1: vboxnet0 state: up speed: 10 Mbps duplex: full mac: <filter> 
           IF-ID-2: wg-client1 state: unknown speed: N/A duplex: N/A mac: N/A 
Drives:    Local Storage: total: 2.96 TiB used: 2.16 TiB (73.0%) 
           ID-1: /dev/nvme0n1 vendor: Kingston model: RBUSNS8154P3256GJ1 size: 238.47 GiB 
           ID-2: /dev/sda vendor: Seagate model: ST1000LM035-1RK172 size: 931.51 GiB temp: 41 C 
           ID-3: /dev/sdb type: USB vendor: Western Digital model: WD Elements 25A2 size: 1.82 TiB 
Partition: ID-1: / size: 91.17 GiB used: 57.70 GiB (63.3%) fs: ext4 dev: /dev/nvme0n1p5 
           ID-2: /home size: 821.50 GiB used: 547.91 GiB (66.7%) fs: ext4 dev: /dev/sda2 
Sensors:   System Temperatures: cpu: 74.0 C mobo: N/A gpu: nvidia temp: 70 C 
           Fan Speeds (RPM): N/A 
Info:      Processes: 425 Uptime: 33m Memory: 19.33 GiB used: 9.02 GiB (46.7%) Init: systemd runlevel: 5 Compilers: gcc: 9.3.0 
           Shell: bash v: 5.0.17 inxi: 3.0.38 

Command 8:

$ nmcli device wifi list
IN-USE  BSSID              SSID                              MODE   CHAN  RATE        SIGNAL  BARS  SECURITY  
*       1C:AB:C0:21:E1:C8  8D                                Infra  1     270 Mbit/s  100     ▂▄▆█  WPA1 WPA2 
        1C:AB:C0:22:3F:B8  8_A                               Infra  6     270 Mbit/s  67      ▂▄▆_  WPA1 WPA2 
        0C:9D:92:53:8F:71  CHU_ Home                         Infra  8     195 Mbit/s  52      ▂▄__  WPA2      
        1C:AB:C0:DB:BC:B8  77-7F                             Infra  11    130 Mbit/s  50      ▂▄__  WPA1 WPA2 
        F4:30:B9:E1:8D:0A  DIRECT-09-HP DeskJet 5820 series  Infra  11    65 Mbit/s   49      ▂▄__  WPA2      
        98:DA:C4:F9:E4:CE  CCL                               Infra  3     270 Mbit/s  42      ▂▄__  WPA2      
        60:A4:B7:3D:37:A7  TANT                              Infra  4     130 Mbit/s  37      ▂▄__  WPA2      
        5C:92:5E:C3:E0:30  mkmkmk                            Infra  5     270 Mbit/s  35      ▂▄__  WPA2      
        74:DA:88:B2:89:B6  DiDihome                          Infra  2     195 Mbit/s  34      ▂▄__  WPA1 WPA2 
        40:9B:CD:A4:38:A0  dlink-38A0                        Infra  1     130 Mbit/s  32      ▂▄__  WPA1 WPA2 
        FC:4A:E9:4D:BF:32  56N9F                             Infra  8     130 Mbit/s  32      ▂▄__  WPA2      
        AC:20:2E:EB:CE:58  110-8FB                           Infra  6     270 Mbit/s  27      ▂___  WPA1 WPA2 
        B8:55:10:44:FA:D4  pumpkin                           Infra  6     135 Mbit/s  27      ▂___  WPA2      
        CA:6C:87:FD:EE:54  stobene                           Infra  11    65 Mbit/s   27      ▂___  WPA2      
        C4:12:F5:40:89:A8  D-Link_DIR-612                    Infra  1     270 Mbit/s  20      ▂___  WPA1 WPA2 
        74:DA:88:B2:89:B5  DiDihome_5G                       Infra  157   270 Mbit/s  17      ▂___  WPA1 WPA2 

iperf test output following @matigo 's solution (post-reboot)

# iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size:  128 KByte (default)
------------------------------------------------------------
[  4] local 173.18.61.138 port 5001 connected with 49.212.186.177 port 58582
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-14.7 sec  7.75 MBytes  4.43 Mbits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 47048
[  4]  0.0- 5.0 sec  35.0 Bytes  56.0 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 48766 (peer 29797.29556.29797-unk)
[  5]  0.0- 5.0 sec  4.00 Bytes  6.34 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 49782
[  4]  0.0- 5.0 sec  35.0 Bytes  56.0 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 52368
[  5]  0.0- 5.0 sec  4.00 Bytes  6.40 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 53856
[  4]  0.0- 5.0 sec  35.0 Bytes  56.0 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 56368
[  5]  0.0- 5.0 sec   243 Bytes   389 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 57994 (peer 29797.29556.29797-unk)
[  4]  0.0- 5.1 sec  4.00 Bytes  6.33 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 60388
[  5]  0.0- 5.0 sec  1.00 Bytes  1.60 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 33430
[  4]  0.0- 5.0 sec  5.00 Bytes  8.00 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 35588
[  5]  0.0- 5.0 sec   289 Bytes   463 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 36804 (peer 29797.29556.29797-unk)
[  4]  0.0- 5.1 sec  4.00 Bytes  6.27 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 39110
[  4]  0.0- 5.0 sec  1.00 Bytes  1.60 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 40280
[  5]  0.0- 5.0 sec  18.0 Bytes  28.8 bits/sec
recvn abort failed: Resource temporarily unavailable
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 42074
[  4]  0.0- 0.0 sec  0.00 Bytes  0.00 bits/sec
recvn abort failed: Resource temporarily unavailable
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 42078
[  5]  0.0- 0.0 sec  0.00 Bytes  0.00 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 42088 (peer 12992.43009.275-unk)
[  4]  0.0- 5.0 sec  22.0 Bytes  34.9 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 43546
[  5]  0.0- 4.8 sec  20.0 Bytes  33.1 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 45790 (peer 3338.3338.18245-alpha)
[  4]  0.0- 4.6 sec  40.0 Bytes  69.0 bits/sec
connect failed: Connection refused
connect failed: Connection refused
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 47048 (peer 14901.12336.12557-unk)
[  5]  0.0- 5.1 sec  45.0 Bytes  69.9 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 48896 (peer 3338.3338.18245-alpha)
[  4]  0.0- 5.1 sec  40.0 Bytes  62.3 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 50210 (peer 3338.3338.18245-alpha)
[  5]  0.0- 5.1 sec  40.0 Bytes  63.4 bits/sec
recvn abort failed: Resource temporarily unavailable
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 52430
[  4]  0.0- 0.0 sec  0.00 Bytes  0.00 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 52444 (peer 116.25971.29812)
[  5]  0.0- 5.1 sec  37.0 Bytes  57.8 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 53996
[  4]  0.0- 5.0 sec  52.0 Bytes  83.2 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 56104 (peer 29797.29556.29797-unk)
[  5]  0.0- 5.1 sec  4.00 Bytes  6.33 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 57490
[  4]  0.0- 5.0 sec  50.0 Bytes  80.0 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 59838
[  5]  0.0- 5.0 sec   210 Bytes   336 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 32774
[  4]  0.0- 5.0 sec  18.0 Bytes  28.8 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 34698 (peer 18245.21536.12064-unk)
[  5]  0.0- 5.1 sec  18.0 Bytes  28.5 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 35982 (peer 12081.11824.3338)
[  4]  0.0- 5.0 sec  52.0 Bytes  82.4 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 36596
[  5]  0.0- 5.0 sec  22.0 Bytes  34.9 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 38688
[  4]  0.0- 5.1 sec  21.0 Bytes  33.2 bits/sec
[  5] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 39754
[  5]  0.0- 5.0 sec  1.00 Bytes  1.60 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 41736 (peer 29797.29556.29797-unk)
[  4]  0.0- 5.1 sec  4.00 Bytes  6.29 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 9.132.28.227 port 42864 (peer 29556.24948.29556-unk)
[  4]  0.0- 5.0 sec  4.00 Bytes  6.34 bits/sec
[  4] local 173.18.61.138 port 5001 connected with 49.212.186.177 port 59900
[  4]  0.0-12.7 sec  6.88 MBytes  4.55 Mbits/sec
Client
Client connecting to 49.212.186.177, TCP port 5001
TCP window size: 85.0 KByte (default)

[  3] local 10.10.10.2 port 59900 connected with 49.212.186.177 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-11.0 sec  6.88 MBytes  5.26 Mbits/sec

While the Bandwith and Transfer on the client side seem high... that is not what I am experiencing most of the time... I still luck to break 800KB transfer.

Being more clear, there are periods when wifi works as it should and I can 3, even 4 MB transfer rates..but this tansitory... it might last for 30 minutes, an hour, then instantly drop to 50KB/s at random. Also, it is always slow at boot time.

Answer 1

A colleague had this on a recent Dell notebook and we worked the problem out to be the TCP segmentation offload for the wireless interface. Disabling it via ethtool resolved the issue.

This is how it was done:

0. Open Terminal (if it's not already open)
1. Install ethtool (if it's not already installed):

   sudo apt install ethtool
   

2. Disable the TCP segmentation offload:

   sudo ethtool -K wlp0s20f3 tso off
   

   ^{Note: The device name wlp0s20f3 was copied from your question. Be sure to change it in the event the name on your system has changed.}
3. Test your transfer speed via iperf3 or another tool of your choosing:

   [ ID] Interval           Transfer     Bitrate         Retr
   [  5]   0.00-10.00  sec   627 MBytes   511 Mbits/sec    0             sender
   [  5]   0.00-10.00  sec   628 MBytes   510 Mbits/sec                  receiver
   

If this works and you would like to make this setting permanent, you can set a udev rule to disable TCP segmentation offload at boot:

1. Create a .rules file:

   sudo vi /etc/udev/rules.d/95-no-tso.rules
   

   ^{Note: Feel free to use a text editor of your choosing.}
2. Run the ethtool command against all wireless devices:

   ACTION=="add", SUBSYSTEM=="net", NAME=="wlp*", RUN+="/usr/bin/ethtool -K $name tso off"
   

3. Save the file and get on with your work

This is not a perfect solution, but it has resolved the issue well enough to make it an acceptable one.

Answer 2

The Intel Killer Wi-Fi 6 AX1650 has Integrated Bluetooth. So you might be suffering from widely reported interference between WiFi and bluetooth (e.g., 1, 2, 3, 4). There are several actions you can take to test this, and then to fix it if you find this is the problem. You seem to have some familiarity with Ubuntu, and an above-average drive for solving the problem, which helps a lot.

Info to post

Please post the following info

1. Output of commands

    $ uname -a                     <-- DONE
    $ sudo lshw -class network     <-- (PARTIALLY) DONE
    $ ls -al /etc/pm/config.d/
    $ ls -al /etc/modprobe.d/
    $ lspci -knn | grep Net -A2
    $ modinfo <your wifi driver>
    $ sudo iwlist freq
    $ sudo iwconfig
    $ inxi -Fxz
    $ nmcli device wifi list
   $ sudo lsmod | grep iwlwifi
    $ iwlist scan | egrep -i 'ssid|quality'
    $ cat /etc/modprobe.d/iwlwifi.conf
    $ grep [[:alnum:]] /sys/module/iwlwifi/parameters/*
    $ lsusb
   

2. Brand/model of your computer

Things to try

Post the resulting behavior / output.

You have driver iwlwifi. So try:

1. Using driver options (parms): sudo tee /etc/modprobe.d/iwlwifi-opt.conf <<< "options iwlwifi bt_coex_active=N power_save=0 power_level=5". If that doesn't work, you could add 11n_disable=1, disable_11ac=1, disable_11ax=1. Reboot.
2. Disabling bluetooth. You can do this via CLI with systemctl stop bluetooth, via GUI with Settings -> Bluetooth -> Move the slider at the top right, or perhaps via BIOS configuration. Reboot.
3. Disabling the 5GHz band in the router.

Related:

1. https://bbs.archlinux.org/viewtopic.php?id=247705
2. https://www.reddit.com/r/archlinux/comments/k7h5iw/poor_wifi_performance_killer_wifi_6_ax1650_dell/
3. Killer WiFi 6 AX1650 in Ubuntu Doesn't work at Gigabit (solution based on backported iwlwifi driver, but you say you already tried this).
4. https://www.intel.com/content/www/us/en/support/articles/000058909/wireless/intel-wireless-products.html (same).