@TP-Link Thanks but this doesn't fix the problem - the issue is that I can't configure it on the main Deco, which means there are no fully-hardwired connections available anywhere else on my network. I want to be able to use the second port on the main deco for the network, even if VLAN is configured. That way I can attach a network switch and have some hardwired connections. Otherwise every computer in the network has to be on the wireless, either directly or over the wireless backhaul.

@TP-Link I do only want to use Internet on the second port, but I saw on the screenshots on the page you sent that it says you can only use the second port for IPTV. If that is no longer the case, I will try setting up the device again. Thank you.