😎 Debian.
If I weren't into VR, I would have literally no reason to use any proprietary software on my computer besides the bootloader (which I would of course also like to replace). I'll get an index soon, as I've heard it runs on Linux, so that'll be very cool.
So the HTC Vive works with FOSS software but the index doesn't? Oh man... I mean, if I'm gonna play VR games, those are gonna be mostly proprietary either way, but oof.
I tried to get my cv1(Original oculus rift) up and running with OPEN HAD but it is so complicated to me, it feels more like some completely standalone software which one needs to understand the entire codebase to even use it... And positional tracking also doesn't work yet, so ya can just look around
Statistically you use an Oculus headset. Someone is currently working on a minimal runtime called Oculus Ameliorated that doesn't have the shitty Dash performance overhead. It's currently in Patreon-only alpha. Here's her Discord.
As someone else mentioned, Steam is still proprietary, but at least getting rid of the resource heavy Meta runtime for their headsets is something to look forward to.
I feel the need to clarify based on the phrasing of your response. Oculus Ameliorated doesn't replace SteamVR. It replaces the Oculus runtime so you can use SteamVR without the extra overhead.