Don’t use the same account for 2 different people. Create another and use Steam Family sharing to fix your issue.

although you still won’t “own” your games, but that’s the life of a PC gamer. Best you can do is buy from GOG or find/run shady cracked versions.

I use my steam deck docked primarily to stream from my main PC to my living room. I haven’t noticed any battery degradation when I do use it in handheld. I got it March 2022.

Also if you happen to be using Emby as a media server, the emby theater app image supports controller :)

Retrodeck in your case then if you just want a simple setup.