My iMac Pro is running 13.4.1 and has no ethernet option in the Network Connections list. Only Wifi and Thunderbolt. I've tried deleting them all and re-adding them to no avail.
That's crazy...yeah, I would try @bogdanw's suggestion and if that doesn't work, then to contact Apple Support. The ethernet port might've become defective and may need to be replaced. However, that might be a very small possibility that is the case as I have never encountered an ethernet port breaking down...