Long story short, W2016 server moving from HV to AHV. VirtIO drivers are installed (before migration) but whenever the machine boots after migrating to AHV, it's bsods with inaccessible boot device. If I go through the whole booting to recovery, deleting the driver and injecting the driver, it boots up but that's a lot of manual handling.
When MOVE migrates to AHV it boots up as SATA drive then it seems to clone the disk and reattaches it as a SCSI drive. It boots to the desktop as SATA but then as a SCSI drive it fails, so the driver issue makes sense. The issue is why the drivers are not working when they're installed on the HV machine before migration and don't work after.