Double check your graphic settings in both Windows 11 and if your using external graphic software.
i am running Windows 11 really good now i checked out all the hidden features and settings very time consumer but its configured now and no issues.
The only thing i would like to see is boot up taking to long to get into Desktop timed it 2 minutes and 39 seconds all up Windows 10 40 seconds, Windows 8 and 8.1 37 sec, Windows 7 34 secs, Windows xp 32 seconds.
I have Windows 11 installed on two computers as of 6th October 2021 both return the same boot up times from power off to desktop.
Overall once configured Windows 11 is actually better than Windows 10 feel bit like the old Windows 7 with Vista security overlay add benefit Windows 10 features.