First please try to reset the graphics settings to default in the game options.
Also try the recently added OpenXR headset type in the config app. Will also work with Oculus headsets after making Oculus your OpenXR runtime in the Oculus PC app (Settings > General > OpenXR-runtime)
If that does not help, there probably is another program on your PC that also hooking into the game, causing a conflict. E.g. some GPU tool, streaming app, FPS counter, chat app. etc. The best way to trouble shoot that is disabling everything you have running in the backround.
The trouble shooting guide on top of this sub forum has more details on the matter.