I'm also "lucky" to have a Goodwe inverter which has the same issue, my model is Goodwe GW8000-DT. I find it utterly annoying not to be able to shut off the ap mode when it already is connected to wifi. Have researched lan-modules but have not found anything that could work. So I'm stuck with the inverter until the end of time, or until it stops working. Next inverter will for sure not be from Goodwe...