It has been a few years since this question was asked. As far as I can tell, Lightburn still can’t run grblhal machines via Ethernet despite it running them fine over usb, and my grblhal cnc machine runs fine over ethernet using various gcode sender software. My machine runs on a teensy 4.1 based controller. Now that grblhal machines with ethernet are more prevalent, is there a possibility this will become available in Lightburn?
I suspect, LB can do this as well then. If you can control it via USB, the protocol is fine. Then it’s more up to configuration, I think. Did you set the correct port in device settings? It’s not enough to set the IP during setup. I controlled multiple lasers via network using FluidNC, grblESP32 and (I think) grblHAL as well. The interfaces are all the same, iirc.
Maybe show the exact configuration you tried for your machine.