So what supposed good are "cloud saves" if every time I install a game on a new PC and start it the first time, it's syncing a blank save game up to the cloud, rather than downloading what's on the cloud to the new PC?

Why can't I manually choose, "download" or "upload" at any time? Why can't I browse what's in there?

No, downloading always comes first (at launch) and syncing at exit.

Or, it might be because Galaxy gets all confused if you have a redirected profile stored elsewhere than your default location for some games.

Of the games I've tested it with on the computer in question, it's only seemed to work for FTL and Stardew Valley. Zodiarcs and Kingdoms/Castles definitely don't seem to work.