New build. Similar issue.
Using a new H470 motherboard: www.asrock.com/MB/Intel/H470M-ITXac
It has 2 NICs: An Intel I219V, and a Realtek RTL8125BG
I was able to successfully disable the realtek NIC in BIOS, but Unraid would not pickup the Intel NIC while booting up. Tried disabling bridge and bond mode, but would be greeted with something along the lines of "eth0 not found"
The Realtek NIC is working now in the latest beta, but I'm not sure why the Intel one wasn't getting picked up. I'd rather start adding data to my array on a stable version