Hey, i have had the same trouble on an DL380 G9. Those bioses don’t support booting from PCIe at all. My server can’t even boot from drives from the Raid controller in IT-Mode.
I would suggest, by proxmox being a hypervisor, to just install proxmox on a single SATA disk and try to boot from there. This is what I have done in the end.
You can then use your NVMes as storage pool. Also you bifurcation can always also be a problem when trying to boot from those devices.
I would also as a last call try to disable bifurcation and see if one drive will show up. Maybe then you could use 2 real PCIe slots with cheap m2 to PCIe adapters.
Does it really matter? I mean you can’t be faster than light, wich is around 300km/ms which we pretty much are. I see this more as a bandwidth type of improvement. In theory we could do 65ms around half the globe with a diffct fiber connection and about 900 trillion watts of energy but thats not really the use case I think.
A better improvement would be WiFi and 5g stability and latency. I loose more latency over WiFi than over my entire connection to any server I need.