I posted this in the ClockworkPi Forum as well.
i had the issue of Ubuntu 22.04 not connecting to my 5Ghz wifi using the onboard CM5 device even though my other devices were connecting to it just fine. even after all the hardware mods with long antennas etc, i finally figured it out.
in Ubuntu at least, power_save must be off.
after loads of testing, this is the setting that would make it work reliabily.
you can set this up by using$ sudo iw dev wlan0 set power_save offor by using NetworkManager$ sudo vi /etc/NetworkManager/conf.d/wifi-powersave.conf
[connection]
wifi.powersave = 2
Once that is done… Wifi would be stably connecting to 5Ghz thereafter.
Hope this helps someone.