This is interesting, I'm not sure I fully understand how this compares to their UNAS offerings. I can't remember off the top of my head if UNAS does m.2 cache drives.
I bought the 8-bay UNAS ($799.00) but have yet to put a drive in it yet since the costs are out of control for hard drives currently. I'm still using my 2x 12-bay Synology for now.
I hope they don't abandon or lose focus of their UNAS offerings (and/or they get better) since I had planned to buy 2-3 more 8-bay UNAS units once I can afford the drives for them.