I have a Steam bug if anyones having issues with SteamVR and not the game.
If the game opens fine and displays on your screen, but Steam VR doesnt seem to detect or open it in VR, go to your SteamVR settings (not the same as steam settings), there should be an OpenXR tab, and it should say the Client OpenXR Runtime is SteamVR, if it's anything different, then there will be a button to set it back to SteamVR.
Other things might cause this error but this is what fixed it for me.