I just installed Start 11 yesterday and I'm having a bit of an issue with it.
I am not using the developers version. I did an upgrade from windows 10 on 10/11/21
The issue I'm having is the background keeps flickering on occasion when I click on the start button.
It's a bit annoying but I know this version is still beta and hopefully the issue will be addressed in later releases unless you have a fix for it now.