Hello
I have four pieces in my QNAP TS-451+-8G
as Raid 5.
Works flawlessly...

I don't have this disk myself, but QNAP NAS can also use 18TB disks. People in the community have already done this successfully. If the QNAP NAS has the new QTS 5.0 upgrade or is capable of it, this is certainly not a problem.