First of all, the guide presented on the forum, by Fernando in which this NVMe mod is based, it’s for booting Windows OS on older motherboards.
The Optane disk it’s only used as intended, as acceleration drive, not a main OS or a NAS system.
Third… maybe the post from this user experience can help you: [HowTo] Get full NVMe Support for all Systems with an AMI UEFI BIOS - Special Topics / NVMe Support for old Systems - Win-Raid Forum (level1techs.com)
Good luck.