Hi guys, I noticed that there is already an OBS fix here.
I tried it out, but I have to say that it has its little problems, e.g. with opening the scoreboard.
However, because I was interested in the underlying problem,
I decided to play around in the NVIDIA settings
and found an option to change the main render method.
"Vulkan/OpenGL present method" as seen here:
In your GameCapture settings of OBS, the option "Capture third-party overlays (such as steam)" has to be enabled: