As the title says I have a x570 pro wifi motherboard, it has 2 nvme slots and while my first nvme shows up the second does not. I have reinstalled windows 10, updated to latest bios, looked into disk management (not there even after rescan), looked in bios (not there only see my first one) and device managers. (Nvme worked when testing on different motherboard so it should be okay), also reseated it a few times in the process.
Try booting with just the one that isn’t being recognized in. Try swapping their placement and have just the os drive in but in the slot that isn’t recognizing the one drive.
Unfortunately my boot drive switched to back slot is not being recognized :(, so this might be an issue with the slot itself
Check in the bios to see if you have to turn the slot itself on. Also check forums to see if anyone else has this issue.