Ah yes forgot about that despite actually using it! AFAIK it can support SteamVR because my goal while tinkering with it was testing SteamVR on the Apple Vision Pro via ALVR (Air Light VR). So yes it can be done, I even made ALVR work on the SteamDeck more than a year ago, just to tinker.
Anyway back to Steam Link does work on Linux, sadly streaming VR does not work on Linux, at least today when I tried and despite having SteamVR installed. Maybe some tinkering is required.