I switched my router to ethernet only years ago, and have slept much better ever since. I have read that our bodies perceive Wifi as light, and this interferes with melatonin production.

Also, ethernet is faster and more secure than Wifi. And you can have tons or mirrors in your apartment without worrying about blocked signal. In fact, I have purposely installed tons of mirrors on the exterior walls of my apartment in an effort to help block other people's Wifi from entering my apartment. This is no small feat, as I live in a densely populated neighborhood.