I use a Valve Index on GNOME as well, so here’s a few things:
VR doesn’t work yet on GNOME Wayland, you need to select GNOME on Xorg when logging in
Sometimes the LEDs are red and the headset doesn’t get detected, just unplug the cable and plug it back in
You might also need to press on the cable where it connects on the headset sometimes, it can become a little loose
Use CoreCTRL to manually set the GPU performance profile to high, it doesn’t do that automatically for some reason and there’s a huge performance difference
If you have the issue that moving your head makes it look like the image is jumping back and forth, go into the per-application video settings of the game from SteamVRs menu and turn on Legacy reprojection
This only happens when I have very low FPS, the CoreCTRL thing fixed it for me without having to use this option
There’s an older SteamVR version for Linux you can select as a beta option for SteamVR in Steam but I’d actually not recommend using it, it only works when games use Proton 5 and there are newer games that don’t work with a Proton verison that old. A lot of the issues the regular SteamVR version had are fixed now and it works pretty well for me.