I'm jealous you're even able to play it on X11. I've played it exclusively on Windows purely because VR on Linux is too buggy with my setup. At first the VR window only showed on my desktop and not actually on my Valve Index, and after finding a workaround it only plays at 90Hz with stuttering. Even if I manage to play through that there is the issue that audio doesn't play through the headset and you can't configure audio devices from within SteamVR. It's a big mess honestly...
Monado (a FOSS OpenXR runtime) works fine however, I wish Steam just used that underneath...