I had to do some research on this to get a better understanding of that as a solution and the legal considerations around it, and It seems to me there is a legal white zone where this approach is appropriate.
Under the US configuration, the maximum transmit power is 23dbm and both DFS and non-DFS channels are selectable, however for me.. all channels seem to be suffering from DFS cutting the radio off even if the channel selected is within the legal range. So if this behavior is erroneously overcorrecting and can be disabled via the solution above, I'm still within the legal white zone by going below 23dbm transmit power and utilizing a non-DFS channel.
Yes, that zone is called Panama, a small independent republic in Central America, roughly 75'000 km² in size and inhabitated by just over 4 million citizens.
IEEE 802.11d is evaluated by modern wireless clients, messing up both your client's regulatory settings and that of your neighbours. As a result e.g. all you Intel wireless cards in notebooks and desktops will only give you access to 5 GHz channels after a passive scan reveals unanimous agreement about your region (yes, one bad neighbour can create real trouble here).
If you do stay within the DFS-less frequency ranges (ch36-ch48), DFS is not necessary and not in use, any remaining problems would not be caused by DFS or radar events in your environment. Changing the region settings will not change this, you merely extend the frequency range claimed not to be DFS encumbered into ranges you certainly aren't allowed to use without DFS.
lol, I hear you. I was going under the assumption that changing the country selection for your router isn't illegal. Operating said router outside of the legal signal and strength range for your country is.
According to what you're saying, does this mean all wireless access point devices under IEEE 802.11d is transmitting the country code, ex "US US US US PA US US US"?
DFS was a strong theory, and still might have something to do with it. Now I'm doubting and looking forward to seeing exactly what is going on when the crash happens. Channels 36-48 have still shown to be more stable than the DFS channels, which raises suspicion.
I've now identified the error message thrown at the exact time of wifi going down.
Thu Jan 13 21:31:29 2022 daemon.err hostapd: 20/40 MHz: center segment 0 (=138) and center freq 1 (=5710) not in sync
Thu Jan 13 21:31:29 2022 kern.info kernel: [ 1931.325762] device 5G left promiscuous mode
Thu Jan 13 21:31:29 2022 kern.info kernel: [ 1931.325937] br-lan: port 2(5G) entered disabled state
Thu Jan 13 21:31:29 2022 daemon.notice netifd: Network device '5G' link is down