Automatic Storage of Encrypted Backup on 2nd QNAP NAS

[frank_g]

Hi
I'm trying to find a solution for an encrypted backup on a second NAS:

I have two QNAP NAS. One sitting at home, the other one is an older TS259 pro+ sitting in a remote place.
I would like to create automatic backups from the home system to the remote system, where
a) the transmission of the data is encrypted, and
b) the data on the 2nd NAS are encrpyted as well (in case the NAS gets stolen).

I tried RSYNC and RRTR alone and both options in the QNAP Hybrid Backup Sync.
Goal a) can be achieved by SSH-security.
However, goal b) can not be achived: There is no option "encrypted files" in QNAP Hybrid Sync App, neither in "profile" nor in "backup" or "sync" - Settings. It looks like the APP is supporting encryted file storage ONLY when the target is Amazon S3 or another Cloud storage.
Am I right ?
Does someone have a good idea how to solve the problem? There was a solution called Cloudberry, but this is no longer supported.

Thanks for any hints.
Frank