It causes stuttering in games, It has something to do with game mode and what it does to full screen rendering, google it, its too complex for me
anyway I have found a fix after a few weeks of annoyance .
You have to disable fullscreen optimization
It's easy. If you want to disable fullscreen optimization for just individual games, navigate to games .exe, right click > properties > compatibility > check "disable fullscreen optimizations."
If you want to disable it for games across the board, globally (which is what I did), go to your general Windows settings (windows key > type "settings" > gaming > game bar > "record clips, screenshots..." OFF > UNCHECK "show game bar when I play fullscreen games microsoft has verified") restart the PC and try your game again in buttery smoothness
Note that you have to turn the game bar off AND uncheck "show game bar when I play..." Just doing one doesn't fully disable the overlay.