I'm having a similar problem where all of a sudden, my Apple TV 4K is getting disconnected from my C4 system. I can sometimes get it working again by restarting the Apple TV from the System menu, but many times even that doesn't do the trick The Apple TV app on the iPhone always works fine. When it works with C4 it seems to work for the entire movies, etc. But when I come back to the system either later in the day or the next morning, it not longer connects and works.
My dealer set me up with the official Apple TV driver a few months ago, and it has been working fine for many months, so something has changed recently and I'm not sure what. Possibly an Apple TV update? This problem just started a few days ago. I have not tried rebooting my EA3 controller yet, maybe I should try that.
Any help would be appreciated.