The enx interface is a virtual interface on Supermicro boards used for communication between the OS and the BMC. This can be configured in configuration → BMC settings. It’s used to provide updates via in-OS utilities (i.e. Supermicro Update Manager). Source.
You mentioned there are three ports but I can only see two there (eno1, eno2). Neither of them have picked up a link-local address so it’s probably that they aren’t connected. Try switching ports and confirming that DHCP is enabled on both of those interfaces.