This one's going to be short. I was able to boot armbian from usb into a partially working desktop, but even here I cannot access the nvme. This leads me to believe the problem is more fundamental, something like this. I don't see those exact error messages but this seems to be the most likely cuprit. And without an accessible nvme drive I'm completely stuck.

Armbian image is currently on the 6.3.13 kernel while latest is 6.5.1. Maybe the fix is in there already. I'll try updating this and see if it makes a difference, but that's task for another day.