Since you mention QNAP, an alternative if you're mostly just looking for a NAS then an old computer with TrueNAS (formerly FreeNAS) is a nice alternative.

You don't need more than about 4GB of RAM, however ZFS is quite good at using it for cache so the more the better.

Anyway, whatever you do, don't enable deduplication. You can't simply turn it off and it imposes sever limitations.