The benefit of running TN in a VM on QNAP is simply that you can then do TN to TN replication. On a stock QNAP, you cannot install TN because the flash drive is only 500MB and TN won’t even install. So, short of upgrading the hardware, there is no other way to get TN running in a QNAP.
I decided to upgrade the flash and RAM and will then attempt to install TN on bare metal on a QNAP server. Since it’s a backup system for me, it should suffice and cost me $50 to do the upgrade.