It won’t have the same performance as a PS5, but the new Minisforum MS-A1 with a user-upgradable CPU is a really interesting proposition. The Ryzen 8700G is pretty good, but I would expect solid upgrades to be available in the next few CPU generations.
I currently have an Nvidia Shield Pro (2019), and it’s fine. I have Moonlight installed and can stream from my desktop PC using Sunshine (I do this on my Steam Deck, too), but I don’t expect that Nvidia will make a replacement, and I don’t know if I would get it if they did.
The software outside of Steam’s big picture mode isn’t ready for a full Linux couch experience, but it’s close. The two projects to watch are KDE Plasma Bigscreen and Waydroid (some people are starting to get Android TV working) which would be a nice bridge to use apps designed for a TV UI until native Linux versions become available.
Good. Keeping it the same means that the original Steam Deck will remain a target device for game developers for longer.