With the 21.02.2 release, it fails to enable WiFi 5GHz on TP-Link Archer A6 v3. After enabling, the router reboots, and WiFi 5 GHz reverts to disabled state again. Enabling WiFi 2.4 GHz seems to work apparently.
I should add that this issue with WiFi 5 GHz was not present in the 02/15/2022 snapshot.
In fact after upgrading to the 21.02.2 release from the snapshot, with my configuration preserved, made the router inoperable and it seemed bricked with LEDs going haywire. However, I activated the failsafe mode and reset it through the firstboot command over SSH. Only after that the router became operational again, and I was able to access LuCI over LAN. Following that I discovered the 5 GHz WiFi issue, and perhaps the upgrade also rendered the router unusable due to the configuration (that was preserved during the upgrade) already having 5 GHz enabled.
I hope this can be fixed asap, as this upgrade may render this router unusable, and perhaps leave it in a bricked state, for other people as well.