Not sure if this will help anyone else, but I couldn't find anything online about this and thought I'd share this with online just in case!

I just started playing Outer Wilds on the steam deck for a week or so, and was immediately in love with it. I decided to install it on my PC (popOS) to see how it looks with cranked graphics, and I could not for the life of me figure out how to sync my cloud saves! For some reason the deck kept saying the saves were syncing fine up to the cloud, but my pc kept sticking at 'checking....' when I asked it to sync...

In the end, I ended up finding a setting in the steam client that enables compatibility for every title in steam that isn't Linux native... when I flipped it on, Outer Wilds (along with like 4 other games in my library) all immediately resolved their bugged cloud sync!

So, I guess, steam will complain that it can't get your cloud saves to download, when really it doesn't have a compatdata folder for the saves to download to. Kinda jank!