Workspaces on a Mac are stored at (User)>Library>Preferences>Adobe Photoshop (version) Settings>WorkSpaces (Modified)> .... .psw
It seems that there's some system permisison issue on that folder, or your user library. While Apple doesn't give us a direct way for a non-tech to troubleshoot this (it would involve checking read/write permissions on each folder in the path), that Full Disk Access usually does the trick. Perhaps revoke the Full Disk Access, restart the computer, and reinstate the Full Disk Access (all directly in the Security and Privacy System Preference) will resolve this. Otherwise, I'd suggest running Disk Utility on your drive.