Why do people try to force macOS things that it does not like to do? macOS does not like not apple hardware, period.
For backups use a NAS. You can find from completely plug and play options to bring your own machine ones.
"Not Apple hardware" meaning an external disk? It's not like the NAS is Apple either. They don't sell NAS or external disks anymore.
"Not Apple hardware" meaning an external disk? It's not like the NAS is Apple either. They don't sell NAS or external disks anymore.