If your controller is not connecting to your WiFi network, here’s what worked for me. I was running the setup process on my iphone 7 where my stadia controller could not connect to my home WiFi network. I logged on to my stadia account on a Samsung galaxy A 10 and ran the same process. And it was successful. Try running the setup on a different device if you can( maybe it doesn’t work for iOS) and it may likely work for you. I hope this helps.