This is intentional by MS and not ethical and also criminal.
They know 99% will just give into into their one drive product and pay a monthly fee for storage eventually as they go over 5GB.
Users pay for their drive and laptops and computers.
One drive very sneakily takes all your desktop and document data, stores on one drive and syncs it.
Then if you disable sync and have to manually move docs out of OneDrive folder that has now become the main folders, your documents and desktop just point to one drive.
But even after manually removing all your files form OneDrive to local desktop and documents, Microsoft does not allow these files to be backed up to local disk backup like external drive.
This needs to be taken to ethics and compliance to regulators and disable this malpractice by Microsoft.