What does having a “FULL HD” (just a marketting gimmick) monitor has to do with the resolution while using an HMD?
On PC you tweak the settings on a game in order to get an acceptable framerate/graphics, basically a compromise, there’s no universal rule bc the performance of your PC is limited by your hardware, which nowadays there’s myriads to choose from and every configuration will vary.
You can either get good enough graphics at 60/90 fps stable or great glitchy graphics bc your PC can barely maintain 60 fps once you actually start playing.