Does idevicebackup/idevicerestore not work anymore?
But agreed, there's no technical reason why the phone can't just accept normal USB-connected storage and store a file in there (in whatever proprietary/encrypted format it wants, but at least the _storage_ is standards-compliant).
Requires payment for backup of any meaningful size.
> locally to your own storage
I don't own a mac. I own Linux. How do I backup iOS to my device? How do I restore it?