it depends on the game, some straight up don't support steam cloud. the only game i specifically know of that doesn't though is Spelunky HD but that came out back in 2013. 99% of your games should just be able to be uploaded through steam cloud and all (or at least most) of your save data will be saved. looking it up Raft does have steam cloud support so you should be good on that. also, on the steam machine i believe they're going to be at least $600 so a steam deck might be a more economical choice, but the prices aren't actually out on it yet so that's just a guesstimate. if you're worried about the steam deck not being a functional computer, it is. it runs on linux which does work differently from windows and might take some time getting used to but it seems as though the desktop mode is a 100% functional, usable computer