It took me a while but I finally figured out that when I log in to my MS 365 account and then switch to the OneDrive App, the list of files I see on the 'Home' page, isn't actually a list of files, it's just pointers to files that have been opened recently. Fine, but why oh why are there no options to mange the list, e.g. to remove an item or clear the list completely
A bit of searching eventually found this topic:
https://answers.microsoft.com/en-us/mso ... fcaa46ab3d
You need to read it all but it's the last post on the first page that explains the weird dance you must do in order to remove items from OneDrive's Home page.
Ken