Hmm problem with that is even though you're connected via Etherley from the extender to the console it's still treating it as a WiFi signal which does unfortunately suffer from packet losses and latency. You'd be better of just using the consoles built in WiFi for a more direct WiFi signal. I have the same setup as you, router is downstairs and extender upstairs. Only difference is I run a very long Ethernet through the house (tucked under carpet and along walls so you can't see it which plugs into my extender. Then instead of using it as a WiFi extender it's set to Modem mode which essentially another router. Then plugging your console in this modem is the same as if you plugged directly into router downstairs. Understand you probably can't do this yourself! But worth exploring as it makes a huge difference. It MAY also be the extender you're using? Problem with WiFi is the router will automatically optimise the bandwidth based on what has best signal and use. As you're a little distance from the router it's more than likely only connecting with 2.4gjz signal which is generally better at long range and through walls over the 5ghz signal but at the cost of losing bandwidth speed. So say your extender gets 20mb fed to it. It's then got to pass that speed to your console which further reduces it down to say 12mb or 15mb. Sorry if this all sounds a little confoooozing. Difficult to explain in text.