That's interesting! I only used the 2 Xiaomis as dumb access points and initially with mixed 5G/2.4G networks, and finally only with separate 5G/2.4G networks (and that was quite annoying, as the 5G networks take so long to become active after starting and have a shorter range).
I always used the latest snapshots and stuck to the dump access point article as much as possible. I don't have any major peculiarities on the network and the glitches reappeared - daily. I ended up restarting the APs every day at 5am and still got the network errors several times a day.
The last 2 days I only used 2.4G networks and it was pretty stable. But I wasn't very happy with that either.
I don't want to advertise the Cudy, but the difference here with our settings is huge!
I can live with the watchdog script.
It automatically reboots the AX3600, when the WiFi firmware crash. The outage is max. 5 minutes (because I check the logfile every 5 minutes).
Maybe it plays a role I use the full wpad , multiple Ssid's and batman-adv 802.11s mesh... I do not use radio0 , but radio1 (ax) and radio2 (2.4g). The ax is the mesh radio. I use channels with lower frequency width that do not require dfs - because dfs crashed my radios pretty often during tests.