I back up to Synology, but always recover from ZFS.

Synology DSM has all kinds of limitations and is slow. Your encryption cannot be like this, you cannot store data in your NVMes, the number of versions must be limited to that, you cannot search snapshots, Hyperbackup explorer provides just one button: Recover (compare that with restic or Borg!), encryption in HB is opaque, ABB is limited to specific kernel versions, information out of SMART is limited, cannot upgrade drives’ firmware, search options are too limited and search is bad, OpenVPN is old and has compatibility issues with newer systems, … I can go on and on!

You cannot compare that with a backup system with ZFS, restic/borg, syncthing and rclone, in the same class!

ZFS is why I bought a QNAP NAS. As far as I can tell, no Synology device supports ZFS, but lots of QNAP devices do.