I beg to differ! I've seen it many times, rather more recently than you suggest. Indeed, my desktop at home has that very issue (admittedly, it's a pretty complex beast, with 12+ drives, some SATA, some SAS, one NVMe - can't entirely fault Windows for getting confused).
But "no longer...
The M2 is showing in the BIOS, yes (under "Offboard NVMe controller configuration" - not that you can actually configure anything there).
I'm using a standard MDT deployment image to install via WDS/PXE. It does not allow for installation on different drives/partitions, but - normally - one can...
I have a new Defiance V - and the Insyde BIOS supplied seems awfully restricted, especially for a machine pitched as a gaming/desktop replacement, and with a price tag to match. Certainly it's very sparse compared to that on my old Optimus.
Is there an advanced mode or something that I'm...