I've found emudeck on the Steam Deck to be surprisingly easy (I have a low tolerance for that sort of tinkering in my spare time). Downloading the right ROMs has been a little more painful (and slow), but once you've got them it's generally been just SCPing them onto the deck and then pressing the button to generate the menu entries.

Admittedly though, I don't care about amiibos or motion controls (I always turn them off when using my Switch).