I’m running Zwift on an ATV4k, plugged directly into a router that is 3 ft from my bike setup.
I run the companion app on an iPhone XR, using wifi only. Signal strength from the router is of course rock solid since it is ~3 feet away from my phone. I have zero issues with other internet-using apps on the phone running from the same connection (although I don’t run anything else concurrently on the phone while I am riding in Zwift).
Recently (last couple of months), I am having constant connection drops in the companion app during a ride. My ATV4k remains in the session, but the app drops from my ride into the font page of the app for a variable amount of time before connecting back into my session. It is getting very annoying since it is making the companion app essentially useless. I can’t find any correlation as to when it happens - it appears random, but it happens almost every session at least once.