FPS drops, maybe related to UI?

Hello,
I might have a very complicated Problem here.
Since 2 days my FPS have dropped from 100-120 to 15-30. I have no performance problems in other programs or games. It seems to be related to the UI, or at least it has the biggest impact. The more UI Apps and higher the UI Resolution, the worse it runs. When im in a Menu, Vehicle Config or Options, the game suddenly runs at 100-120 again and everything moves smooth. Problem exists in Vulkan and DirectX. Doesnt matter if im in safe mode or not. I ran the integrity test on steam and then in the Beam Launcher. It showed me some missing dlls so I repaired both visual c++ 2015-2022 that show in Apps and Features and it still showed them missing. I reinstalled the newest version, still doesnt work.
Some other things I tried were disabling Nvidia Overlay, updating graphics drivers, disabling windows game mode and hardware accelleration, changing graphic settings, deleting user folder, reinstalling the game, run scannow in cmd and doing a virus scan. Nvidia shows a GPU usage of around 95% ingame but task manager shows 30% usage. CPU is at 10%. My computer is good, I have a I9-9900K, 4070, 64GB Ram. My CPU and GPU temps are fine.

I have no clue what else I could do, I hope someone here may have an idea what it could be.