There is no AMI Aptio III… its AMIBIOS8 generation, and no, the guide referes to a DXE driver for AMI Aptio V UEFI bios generation.
Theres this option for it, you may try it: [Experimental] NVMe Option ROM - BIOS/UEFI Modding / BIOS modules (PCI ROM, EFI and others) - Win-Raid Forum (level1techs.com)