Valve Rolling Out Dynamic Cloud Sync For Moving Between The Steam Deck & PC
Steam's Dynamic Cloud Sync can simply be summed up as, "This feature allows players to seamlessly move between Deck and PC instances of the game without needing to worry about exiting the game on the Steam Deck."
Dynamic Cloud Sync builds onto the existing Steam Cloud capabilities and makes it easy to transition to/from Steam on a PC and then the Steam Deck without having exit the game. All modified save game data will be saved to the cloud prior to the Steam Deck resuming from deep sleep.
Dynamic Cloud Sync does require integration on part of the game developers. More details on this new Steamworks feature over on SteamCommunity.com.