Sure, but remember that a full on dock will make your Switch hotter (unless it’s actively cooled, which the original is not), and that may affect both performance (throttling might cause the games to stutter) and devices lifespan.

I don’t know about Steam Deck (so assume it should), but this one works with Switch 2 (and doubles as a capture card).

No, I think the only problem is that Switch 2 won’t output video via most docks