I have 4x - 2TB nvme on Asus HyperX M.2 Gen 4 card in my Synology DS3622xs+ as second nvme only volume in RAID10 for fast files sync and storage using Synology Drive.
Have another 4x -2TB nvme coming that I will put on same Asus AIC as 8TB RAID0 array on my Windows workstation for super fast scratch disk for my database projects.
My 3622xs+ is not a "real" Synology box. It's a custom built Xpenology running ARC loader. By using 007revad's scripts, I'm able to create M.2 volume. Pretty sure you can run Dave's script on any Synology boxes. Go to his Github to get instructions.
https://github.com/007revad/Synology_M2_volume