My Mac mini M2 (Base model) had the same terrible Wifi Performance when I set it up yesterday. I set it up the same location as my previous M1 Mac mini. Wifi reception never was an issue here.
Thanks to the helpful posters in this topic I was able to resolve my issues.
I can confirm the following two options worked for me:
### by hanlanx ###
Disable AWDL will solve the 5GHz connection problem:
Disable: sudo ifconfig awdl0 down
Enable: sudo ifconfig awdl0 up
###
Unfortunately you will lose some functionality like AirDrop oder AirPlay Receiver. So I also tried to switch my HDMI cable as some of you had reported this to be solving the issue.
As I had another spare monitor I switched from my Eizo HDMI Monitor to a DELL DisplayPort Monitor.
Afterwards I enabled AWDL again an restarted my Mac.
Since about 3 hours WiFi is finally working without any further issues.
Still, this is a bad first hand experience and not anyone can change to a different display connection.
I hope it will be possible to fix for everyone via software update.