Microfreezes / stutters when moving mouse in game

This happens noticeably at the login screen, as well. As soon as I move the mouse, its like everything only gets rendered at half fps. The FPS dont drop, i'm steady above 100 FPS and CPU usage is around 40% and GPU around 80%.
This problem is NOT as frequent in window mode, but very rarely still happens. Tried messing around with all kinds of settings, windows settings, processor priority etc.

RX 7800 XT
Ryzen 5 7600X
32GBG Ram
Using an LG B1 as Monitor (144 hz, Freesync, HDR10)
No 2nd monitor

this issue is still happening :\