Heroic Games Launcher supports GoG pretty well. You can install it with Flatpak using Discover in desktop mode.

When you login to GoG and install a game, you will be able to “Add it to Steam” (top-right hamburger menu in game’s view) and it should then be available in your “Non-steam games” in gaming mode.

Other options are Bottles and Lutris

There were some recent fixes to Steam VR but I have never tried a VR headset myself. It should work on Wayland with a compositor that supports DRM-leasing protocol, so basically everything but GNOME.