I own a valve index. I use it only on linux (mint) via proton. I can say that it does work. There are quirks. don't expect it to be seemless. For instance, more than half the time I start SteamVR but have to then "restart" the headset. Once it is working it is working.

Not all VR games support linux but many do, probably a higher proportion than amongst non-VR games. VR games tend to come from smaller developers who are generally not implementing the things that bork linux (eg DRM).

IMho now is not the time to get into VR, on any OS. You need a serious graphic card. Whatever you are running now, you will want something better once you plug in a VR headset. Good luck with that atm.