Jl1994
We all have individidual reasons why screen bother us. People are sensitive to different things.
So it could be that something in windows 11 is triggering you and not someone else.
Also brigthness could be a trigger. But even if the display at 100% brigthness, which generally has a good likelihood to eliminate baclight flicker on screens , you could use things like the chrome extension "dark reader" that Lets you contol brigthness using software only, in a safe way.