I understand the Synology unit doesn’t support volume encryption, but does support encryption of shared folders. I don’t know what shared folders are in the context of NAS. Assuming data on the Synology unit is encrypted within the shared folders, and that volume-level encryption is enabled on the QNAP unit, is the Synology less secure than the QNAP, either to burglary, or via hacking?
Qnap 51+ fairly old. I would consider 51D2 as a replacement.
Qnap volume encryption is not that different then Synology folder encryption. Both methods use the same encryption technology. Instead of having everything encrypted you get only a few folders encrypted. I believe Synology knows that encrypting the entire volume reduces the performance therefore they don’t give this option.
A shared folder is a storage space you can map on your computer and will see next to your C: drive in “My computer”.
Either way, if someone steals a NAS they will need to have a key to unlock this folder.
I hope this helps.