How to fix extremely slow network conection - Ubuntu 20.04 LTS?

Question

Edit below, 2023-12-12:

• The issue has been resolved.

  Turns out it was a browser-related problem.

  After reading all the comments and trying various solutions, I went to check if the browsing speed is lagging in Tor, everything ran smoothly.

  My default browser is Firefox, and settings there were causing an issue. Didn't dig any deeper and just made a fresh install, and now everything is running smoothly at a great speed.

• Pastebin link removed as no longer relevant.

---

Original post below, 2023-12-11:

I've been experiencing extremely slow network connection on my laptop (Acer Aspire E5-575G) both on cable and wireless. It's not a case of internet speed being fine and then suddenly dropping, the speed has been constantly abysmal after turning on the laptop.

Since the laptop is in dual-boot, I checked the other OS and network connection is of normal speed there, so it seems this is an Ubuntu-specific problem. The version installed is 20.04 LTS.

So far, I've tried reinstalling the firmware and disabling Wi-Fi power management - that didn't help. Saw another suggestion with Software & updates -> Additional Drivers, but there's no driver listed for Wireless Network Adapter.

For what it's worth, everything was running smoothly and then this issue appeared out of nowhere. I'm unsure what could be the problem and where to look for possible solutions.

Network controller

Network controller: Qualcomm Atheros QCA9377 802.11ac Wireless Network Adapter (rev 31)
Subsystem: Lite-On Communications Inc Qualcomm Atheros QCA9377 802.11ac Wireless Network Adapter
Kernel driver in use: ath10k_pci
Kernel modules: ath10k_pci

More details:

*-network                    
description: Wireless interface      product: QCA9377 802.11ac Wireless Network Adapter
vendor: Qualcomm Atheros
physical id: 0
bus info: pci@0000:03:00.0
logical name: wlp3s0
version: 31
serial: 3c:a0:67:64:ef:1f
width: 64 bits
clock: 33MHz
capabilities: bus_master cap_list ethernet physical wireless
configuration: broadcast=yes driver=ath10k_pci driverversion=5.15.0-91-generic firmware=WLAN.TF.2.1-00021-QCARMSWP-1 ip=192.168.1.4 latency=0 link=yes multicast=yes wireless=IEEE 802.11
resources: irq:136 memory:b4000000-b41fffff

Ethernet controller

Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 12)
Subsystem: Acer Incorporated [ALI] Acer Aspire E5-575G
Kernel driver in use: r8169
Kernel modules: r8169

More details:

*-network
description: Ethernet interface
product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller  vendor: Realtek Semiconductor Co., Ltd.
physical id: 0.1
bus info: pci@0000:04:00.1
logical name: enp4s0f1
version: 12
serial: a8:1e:84:46:e5:a1
size: 100Mbit/s
capacity: 1Gbit/s
width: 64 bits
clock: 33MHz
capabilities: 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=5.15.0-91generic duplex=full firmware=rtl8411-2_0.0.1 07/08/13 ip=192.168.1.3 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s
resources: irq:19 ioport:3000(size=256) memory:b4204000-b4204fff memory:b4200000b4203fff

dmesg log: https://pastebin.com/LRmeehdx

Please direct me how can this issue be fixed. Apologies if formatting turns out to be bad, I'm on a phone.