I guess you won't be able to recover them.. especially if at some point they were overwritten by a new a corrupt save. Before the fix, I was constantly erasing the whole data from the storage (always 1.7 or 1.9gb) and downloading that saves that were in Larian's storage (around 150mb - only were good). Then - just in case - I was uploading them to PS cloud storage.

It didn't help, because I couldn't save, but now it's working flawlessly again. I could save several times and the size is just 200mb.

If you have any saves synchronised with Larian, maybe just forget about the others, erase everything from the PS storage and sync the game again.