I have to mention that my computer is also running Linux, more precisely MX Linux. And yes, I know that Steam Cloud does exist. My concern is with games that do not support it (or not for certain things, maybe). Would manually moving games from my PC to the deck work? Maybe through mounting the Steam folder on the deck as a network drive or some sort?
Games often don’t put the save files in the game data dir but use some random place in documents or the home directory. The library itself will move and be picked up fine but the saves will have to be sync thinged or rcloned or something manually if they’re not on steam cloud.