Acoording to leaks, new VR headset from Valve won't be competing with index. It's gonna be standalone, probably using steamos3, with new inside-out tracking tech.
I replaced my index with pico 4 and I'm very happy with it. I don't mind compression that much.
Yes, You need to buy app called virtual desktop to stream output from pc to pico. Official pico streaming app seems to be laggy. You play wired or wireless if You have good wifi.