Hopefully someone has had the same problem and found a solution.
I’ve added a usb 3.0 2.5gbe link and adjusted the metric values but it seems that somehow enp2s0 always has priority over it. Is there a preferences files someone that needs adjusting? For info, I have eno3s0 on a different subnet for direct connection to a Nas so that is out of the equation and the idea was to utilise the 2.5gbe for all Plex traffic. But somehow eno2s0 always seems to take the lead.
We need to know your hardware and software information, such as the hardware model, software system version, and so on.
Zimaboard 8/32.
Anyway I fitted a 2.5gbe card on the PCIe slot and that became enp1s0 and has taken over priority. So the answer to the question is if you want to change to the primary nic then go through the PCIe slot, using a UBC port would seem to be ok for assigning for specific traffic ( I could get it set up to take over external Plex traffic) or perhaps to be used on a sub net.