Transfer data backed up to one Apple ID for this imac to another new Apple id logged in on the same imac

I had to remove the Apple id on the affected mac (Catalina is the newest it can install) because it was linked to an Apple ID, and when turning on advanced data protection, because of the age of the imac, it wouldn't allow that unless the imac was unlinked from that Apple id. Did that and ADP was setup, however I couldn't use that Apple id on the imac anymore so I created a new one. After finally being able to login in with that new apple id with help from Apple support (icloud agreement bug), I am logged into the new Apple id on the imac, is there someway I can get whatever was backed up in the cloud for this imac from the other apple id and get it transferred to the new Apple id? For example when I logged out of the old Apple id, the files on the desktop disappeared as well as files in the document folder. I'm sure they are still there under the other Apple id but how to get to them? Thanks.