Hi @ChrisP,
I'm sorry for the trouble you're running into here.
I'm not sure if this will fix things for you, but the rsrecovr package might be able to help with unsaved files: GitHub - jmcphers/rsrecovr: RsRecovr: Recover unsaved files from RStudio sessions
If that's not the case for you (it sounds like your saved files are missing?), could you send a screenshot of what you're seeing in Posit Cloud? Is the File pane empty? What did you run to get the error messages you posted here? If you export your project are the files you expect to see in the export?
Mel