Phoronix article: https://www.phoronix.com/news/Steam-Machines-Frame-2026
Also listed here: https://store.steampowered.com/sale/hardware
Valve has already sent support for the new Steam Controller upstream: https://www.phoronix.com/news/New-Steam-Controller-SDL
I mean, you can certainly pick up a used Quest 2 if you wanted to try it out. There's a handful of exclusive stuff in the Quest store you'd be able to use, but not much of value. Resident Evil 4 VR is about it for the Q2. I think there was a Batman game for the Q3. You'd have access to anything the Steam Frame has access to if you're streaming from a PC.
I think the PSVR2 works as well, but it's wired only.
Half Life Alyx is certainly worth a blast through.
Stories like Ftumch's reply, and the fact that it's owned by Meta 🤮 have deterred me from wanting to try that one.