Chosen Solution
So my Xbox one controller will start flashing then turn off then kick me offline. It does it more frequent than ever right now. I heard something about the wifi card will work and help but I wanted to see if y’all had an answer. How do I fix?
Yes the WiFi card was my initial thought as i read what you explained. it would certainly be the first thing i would try. if you really wanted to put it to the test, keep your controller plugged in with a USB cable to the console. if your internet disconnects and the controller stays connected i am certain its the WiFi card. its a pretty easy thing to replace thankfully. only mission about it is opening the case
There us a known issue with xbox ones being in Instant On. I would suggest changing that to Energy Saving and see if it fixes the issue. Mine was doing the same thing til I found that solution. No more problems since.