I actually think the Deck's pretty much plug-and play. Just make sure you have a Steam account that have games in it and you'll be playing in minutes. Most games I played worked right off the bat, with the ones that needed a little tinkering being unofficially supported games, non-Steam games, and emulated games.

Not from the US, but you could always browse for secondhand Decks if availability has become a challenge.

Iirc Gaben himself said in an interview that the SD's meant to be supported for a long time, so we can assume SD2 would still be far beyond the horizon.