-- Either that, or it's an issue with 'One Drive'.

As far as I can tell, your problem is that there is a MS365 Trial version installed and it just won't go away.

Here are two more Microsoft Tools to try.

Uninstall Microsoft 365 from a PC - Microsoft Support
Be sure to look at the "Not sure which type of install you have?" section.

I've never had much luck with Microsoft "Easy Fix" tools, but just to be complete:
Video: Uninstall Office - Microsoft Support