OK, I repeated the install, this time with nothing plugged into my network port, to simulate what happens when there is no path to the DHCP server.
The install proceeded as before, but instead of asking me for the hostname, I now got a notification that network autoconfiguration had failed.
This lines up with what I suspect you saw.
So, bad cable or maybe incompatible NIC still seem possible issues.
I continued with the install choosing not to configure network at this time
I then saw the bad mirror red screen, like you did. this seems expected when network isn't functional.
I had to back out and not configure an archive mirror
the install completed and I was prompted to reboot after disconnecting the installation media, so I did.
It rebooted into OMV, so i logged in locally with root, then ran omv-firstaid, and chose option 1 to config network.
At this point it listed my intel NIC, so I know that the driver loaded and the nic is compatible with debian / omv.
I configured it to use dhcp with ipv4 and not to use ipv6 and then restarted it with the reboot command.
I then plugged in the cable, 2 seconds later i got the two beeps letting me know that OMV had started correctly.
sure enough I pinged it from another system and it responded correctly.
If you can get into omv-firstaid it will tell you if the nic was loaded correctly, even if you dont have a cable connected.