Just noting that Synology also has their E10M20-T1, which is somewhat similar to this card.

Plugged into my CM4, I was not able to get PCIe to be recognized—my first inclination is there might not be enough power, or the card might be configured in such a way as to not work with PCIe Gen 2 x1? It uses the ASM2812, which says it supports x1, x2, or x4 lane, at 2.5, 5, or 8 Gb per lane though...

I tried a couple different boots with a fresh OS install, and it kept saying 'Link down' for PCIe. Though the Ethernet port would get a link at 10 GbE to my Mikrotik switch, so again, not quite sure why it won't be recognized on the Pi.

It's totally overkill for a Pi, though, so I'll leave it at that.

It's really nice that ASUSTOR includes both a half height and full height PCIe bracket, so you could install this card in a regular PC. That will increase the longevity of this card—as if you end up with an old NAS with one installed, you could pull the card and pop it in any other PC to get a couple more NVMe slots and full 10 Gbps Ethernet for a nice little upgrade.

Pictures: