It is good you posted that video as indeed these have been flying under the radar for most people who do not frequent NAS Compares where we can also find a “print” version as @dolbyman would say:
Looks like the TVS-AIh1688ATX will become available after all so after half a decade you will be able to offer something new - and more capable - to your customers. I really like that they now have 4 2.5" NVME drive slots, that is a big improvement and will finally give some much needed speed advantage for these slots. Hopefully they have not discarded the internal M.2 slots as they would come in handy for the system SSDs.
It is also good to see that they have expanded the TS-hxx77AXU series with a 24 drive version and the new TB / USB4 adapters look interesting, too.