@0x44 Router interfaces don't typically 'change' (i.e., unplug/replug, link up/down) that regularly. In order to have Wi-Fi even, you'd need to somehow get an AP on at least the same management broadcast domain as the LAN interface without directly connecting it... because how else would you expect to be able to connect to and manage it?
Directly connecting a network host like a PC or a server to a router interface is a somewhat unsual setup. @SteveITS's advice to connect a switch to the LAN interface—and then properly test connectivity of any/all devices that will connect to the switch, plus assess overall network stability with that topology—is the right advice.