I've only ever owned a Steam Deck so can't really comment. I used it a couple times intending to use it when travelling by train then sold it because it was too wide/big to really carry around with the carry case. Didn't really see the advantage over just playing mobile games (or doomscrolling social media etc) or playing more indie/basic games on the laptop.

Xbox is fine, it updates itself (firmware/OS updates only take about 5 mins) and the servers are fast enough. There's basically no maintenance. Can be annoying if it's a game you wanted to play at the moment updating but then Steam is the same.

Yes. There are no launchers for games that need to be updated. Everything just automatically gets updated constantly.

The biggest value prop for me with console gaming is that it just works, every time. No GPU/launcher/mod/etc updates to deal with ever.

I've owned some gaming PCs and every time I've learned that I don't want a hobby of maintaining a gaming PC. I want to sit down, in my favorite comfy chair, with a controller (because I've already been on a keyboard all day), and just play.