I'm seeing the same thing as the OP on my OPi PC with a cheap Realtek 8188CUS wifi adapater. Something seems to go wonky with the drivers and firmware after apt-get upgrade from 5.20 to 5.23. After a clean install of 5.20 image (let it reboot for swap, fs resize, etc), plugged in Ethernet, apt-get update, apt-get upgrade to 5.23, reboot. First, dmesg complains about missing firmware. apt-get install armbian-firmware-full corrected that problem. Reboot. Use of nmtui results in stack trace, panic, and reboot.
When I get home I'll post system data (dmesg, syslog, ifconfig, etc).