Greetings Pilots! I found a solution for this, I believe it’s related to windows 11’s Game DVR.
Just few registry edits and disabling it fixed all issues for it.
How to do? Follow steps mentioned in Solution 1 mentioned here:
I was playing Age of Empries 4 last night and had same issue, super low FPS and stuttering when OS am focused the game (with very low GPU usage) and high FPS and high GPU usage when game window is not focsed. I realized that it’s not just flight sim or drivers issue but it’s just windows 11 issue.
I hope it works for everyone 
, Smooth landings!