Regarding the issue of the Elder Scrolls IV: Oblivion Remastered failing to load PC saves on Steam Deck:

[Aegir]

So far, I’ve tried several methods, but the Deck still can’t read saves from my PC playthrough. Considering how Steam was probably still in its infancy during the original Oblivion era, the "faithfully preserved" lack of cloud save functionality is peak Todd Howard humor.

After launching and closing the game on both PC and Deck, Steam Cloud claims synchronization is complete. However, when checking Steam’s cloud save history on PC, the first two entries are new saves created on the Deck at noon today, while the third is my recent PC save (3+ hours of gameplay, post-Oblivion Gate closure). The naming conventions and file sizes differ drastically between platforms: Deck saves (still in the prison cell) are ~160KB, whereas the PC save is only ~46KB. Though sharing the same file type, it appears the Linux-based Steam OS currently cannot read cloud-synced PC saves, and vice versa.

In essence: "We have cloud saves... except they’re platform-exclusive. Good one, Todd."

[Kaito]

This is weird though because I'm having the same problem but between 2 Windows PCs (a desktop and a laptop). Initially the desktop I hadn't played on yet said the cloud save wasn't synched. So I went to turn on the laptop, I started the game, loaded my save (it worked), closed out of the game and waited for it to sync.
Then I checked my desktop and it had indeed synced.
I start the game and no save is present in game.
I haven't checked my save files yet but just wanted to share that it might not be OS related

[Romkslrqusz ツ]

Solution / workaround here: https://steamcommunity.com/app/2623190/discussions/0/604154270792702933/

[Kaito]

Originally posted by Romkslrqusz ツ:

Solution / workaround here: https://steamcommunity.com/app/2623190/discussions/0/604154270792702933/

Thank you very much!