Disable "backup" and you can disable "Files not in a folder" which might equate to Desktop - although that is not explicit nor necessarily confined only to files on the Desktop.
I'm still unclear what is the difference between syncing local folders to OneDrive cloud and "backup".
@Emily: "simply disabling the desktop folder backup leaves you with an empty desktop!"
Yes. OneDrive snatched up sensitive and important files from my Desktop to the cloud - an unwelcome invasion and unexpected security risk.
Unexpected because I had managed to remove any other locations from sync except for Documents and Pictures - only because I was unable to deselect them.
The only thing I want OneDrive for is to sync OneNote - both being MS products I assumed they might be the best combination.
When I found the function to deselect backup for desktop, it immediately deleted all files from the cloud AND the originals it had pilfered from the Desktop.
They were not in the Recycle bin - just deleted from my local machine entirely. Like an automated anti-backup triggered by declining the unwanted backup to cloud option.
I did manage to retrieve them from the OneDrive Recycle bin.
The deletion of all files on the desktop being so blatantly unsatisfactory to the user is the only thing that validates any sense that this universal operation is as I'm sure they would argue their standard and familiar practise of programmatically routine incompetence and not the basis of cyber crime. Uncannily similar as they appear in operation.