The SSH guide that @weirdcraphas mentioned has go to do with logging into QNAP via SSH. You don't need that. I have a similar setup as @huntjules where I required VM Backups folder copied over to my QNAP. At first was a bit of a hustle but realized it was my own "thinking-too-technical" brain misleading me-there really isn't much setup to do. Simply setup Rsync in HSB 3 using the "Active Sync Job" mode, this has the QNAP pull the files FROM Unraid, the other two options will send TO Unraid. Select 'Remote Rsync Server' and fill in the details. Username and Password are your Unraid login credentials and remember to check 'Use encryption port' which is 22. Test the connection then proceed on to select your folders/directories while completing the rest of the setup. That's all😊
A heads-up: the sync process may take a while depending on the size of the source file. Seems QNAP will 'cache', like how Download manager does when downloading, and it'll seem like the sync process is stuck. Be patient.
All the best