Hotspot/Tethering but can't see the network

Question

I'm trying to set up a hotspot (a.k.a. AP, a.k.a. tethering) with my desktop computer's wireless card, which is also is connected to internet via ethernet.

I get the green light in nmcli, but none of my devices can see the network. I've ran into a couple of snags; having to turn radio on via nmcli and also it does not work if it tries to claim the same IP address twice. I've also tried using connman with the same result: all clear on the desktop (i.e. the host AP computer) but devices can't see the network. What's the next in my troubleshooting process?

Here are some deets of what's going on:

ellen% uname -a
Linux ellen 5.3.0-26-generic #28-Ubuntu SMP Wed Dec 18 05:37:46 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
ellen% lspci -nn|grep Network
04:00.0 Ethernet controller [0200]: Intel Corporation I211 Gigabit Network Connection [8086:1539]
(rev 03)
05:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8822BE 802.11a/b/g/n/ac
WiFi adapter [10ec:b822]
ellen% lsmod|grep rtw
rtwpci                 24576  0
rtw88                 471040  1 rtwpci
mac80211              851968  2 rtwpci,rtw88
cfg80211              712704  2 mac80211,rtw88
ellen% ls -d /usr/share/doc/dnsmasq
/usr/share/doc/dnsmasq
ellen% nmcli dev |head -2
DEVICE  TYPE      STATE      CONNECTION
wlp5s0  wifi      connected  Hotspot
ellen% sudo grep hidden /etc/NetworkManager/system-connections/Hotspot-1.nmconnection || echo No hidden
No hidden
ellen% nmcli dev  wifi list
IN-USE  SSID                          MODE   CHAN  RATE      SIGNAL  BARS  SECURITY
*       A lone doorframe in the wall  Infra  1     0 Mbit/s  0       ____  WPA1 WPA2
ellen% ip a s dev wlp5s0
3: wlp5s0: <BROADCAST,MULTICAST,DYNAMIC,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default
qlen 1000
link/ether 80:91:33:7e:80:21 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.8/24 brd 192.168.0.255 scope global noprefixroute wlp5s0
   valid_lft forever preferred_lft forever
inet6 fe80::8291:33ff:fe7e:8021/64 scope link
   valid_lft forever preferred_lft forever
ellen% /sbin/iwconfig wlp5s0
wlp5s0    IEEE 802.11  Mode:Master  Tx-Power=20 dBm
      Retry short limit:7   RTS thr:off   Fragment thr:off
      Power Management:on

I can't check on the clients because they are things like video games, ebook readers, printers etc (that worked fine on my old AP).

Antenna yes. But it has two wires, are they equivalent to each other or does one specific wire need to go to one specific contact?

Update! In /var/log/syslog I found two weird things!
The first:

Jan 24 15:40:38 ellen wpa_supplicant[870]: wlp5s0: CTRL-EVENT-SCAN-FAILED ret=-95 retry=1

I've gotten rid of by adding into a file in /etc/NetworkManager/conf.d like this:

[device]
match-device=driver:rtw88
wifi.scan-rand-mac-address=no

The second:

Jan 24 15:40:37 ellen wpa_supplicant[870]: MGMT: BSSID=5e:6a:80:7b:60:90 not our address

I have no idea. I'm not sure where the "5e:6a:80:7b:60:90" comes from.