You are only pretending you are on a ethernet connection. When you connect a ethernet cable to some kind of mesh/repeater unit or some kind of bridge you are still using wifi. What you are basically doing is connecting a wifi nic to your machine via ethernet rather than a USB cable.
It will still have all the issues of a wifi connection since there is a wifi connection in the hop. This is very similar to issues people who say tether their cell phone to their computer. In that case it isn't "wifi" but it is still a radio signal that can have interference.
Best of course is a ethernet cable all the way to the main router. I suspect you would do that if it was a option already. The next is MoCA but you need coax cable in a room near the router and the remote room. MoCA can get full 1gbit speeds. You can also try powerline networks. This might be slower than wifi but it will be much more consistent latency. The consistent latency is much more important to games since a game only uses about 1mbps when you are playing them. If they are huge downloads you could switch back to the wifi to do just the download if the wifi was faster.
....note tracert does not run long enough to give you valid data. A normal ping command to the various nodes is better for troubleshooting.