With Dynamic Cloud Sync, if they then choose to play on another device (whether a PC or another Steam Deck), their progress will be there waiting for them.
When any Steam device is put to "sleep," Steam will connect to the Internet and proceed with the same upload of save data that happens whenever a compatible game is quit normally.
Should a player put their Steam Deck to sleep, play the same game on a home PC, and then pick up their sleeping Steam Deck to continue the same game, the Deck game will receive a notification about newly downloaded save files!
If a game does not support Dynamic Cloud Sync, the shift from the Steam Deck to a standard PC will be less elegant?As Valve tells devs on Steam, "Any user who suspends their Deck while your game is running and then tries to resume that game on a different device will be prompted to first return to their Deck to close the running process or continue without their most recent save game progress.".
Will the Steam Deck routinely check for an Internet connection in order to upload save files to Steam's cloud service.