the problem with the TVS-AIh1688ATX is the price of the U.2 NVMe drives. Most pro users want a LOT of storage, and unless you are willing to keep transfering your data from the 4 U.2 drives onto the SATA RAID array, this will be crazy expensive.
QNAP can now sell Phison Pascari U.2 NVMe drives directly. A single Phison 7.68 TB U.2 NVMe drive from QNAP is $976, and a single 15.36 TB Phison U.2 drive is $1874. So if you do a RAID 5 with the 4 U.2 drives, that is $7496 for about 46 TB of usable storage. Do you think that people will pay this amount of money ? This is why it’s so hard to get TS-h2490 and TS-h1290FX systems installed. The QNAP pricing is great. The issue is the crazy price of the U.2 NVMe drives. And Phison is CHEAP compared to the other manufacturers.
Bob Zelin