Since then, I've discovered that Apple routers don't play well even with one Xbox, and I was apparently lucky to have had good connection for as long as I did without configuring the Airport and the Xbox, due to the Xbox's preference for unPnp (unsupported by Apple) and NAT forwarding, etc etc.
How to Setup An Airport Extreme - YouTube Feb 09, 2014 How to set up your AirPort Base Station and Guest Network Apr 25, 2017 Danilo's Tech Blog: Configuring the Apple Airport Extreme
Aug 09, 2016
Feb 09, 2014 How to set up your AirPort Base Station and Guest Network
How to Set Up the AirPort Extreme | Macinstruct
Apple’s Done Making Airport Routers, So Try These Instead