In my case, there is no problem to detect drives on DS3622xs+. But you can't create NVME storage pool using WebUI.
In the same time on DS1621xs+ only 2 NVME drives are displayed in Storage Manager, but storage pool can be created with 2 NVME drives.
I'm interested in using M.2 NVMe drives.
Currently i'm using 5 M.2 NVME drives in my system.
Intel Core i5 6500T + noname Chinese MB based on Intel Z270 with PCIE bifurcation support x8x4x4 and 2 NVME slots.
For the rest of NVME drives I use a board from Aliexpress
After testing I stopped on DS920+ loader.
Drives are recognized and I can create the storage volume from Web UI.