How does one re-enable the wired Ethernet port on a Pi 4

[lampy (Gerwin)]

I am not a Linux expert, but perhaps you can find hints in here:

Ethernet and WiFi Setting

That’s probably the way to do it with domestic routers. When I get a new device I first let them connect to the network with DHCP. I then log in the router config and reserve that IP for that device. I then go back to the device and configure static IP. Last thing is I add this to a list in a “cheat” file where I keep the IPs the different ports that the OH server uses etc…