NVMe booting on 12th gen Poweredge

For anyone who just wants the solution without the story, skip to [here](#What if the firmware just had drivers?). For around three years I&rsquo;ve been running a Proxmox server on an R720, for random projects like hosting this exact site. (Also it&rsquo;s just fun to gauge people&rsquo;s reactions when you show them a photo of a big 2U server in your room.) However, for around the past two years…