First step would be to measure the current speeds. Can you try the speedtest app on the TV?
From the DVR PC you can also run a speed test to the TV, but the Channels app must be running on the screen and you must look up the IP of the Apple TV first. Then from the PC you would open in your browser http://x.x.x.x:57000/speedtest replacing x.x.x.x with the IP you found in the Apple TV settings under Networking
We’ve ruled out the antenna. The network connection to the Apple TV is the issue to fix. Where is the Apple TV physically located? Is it in a cabinet close to the floor, for example? How far from your router is it? Generally the higher you can get both the router and the Apple TV with the fewest obstructions, the better.
If you don’t already, make sure you are using the least busy wifi channels possible. Wifi is incredibly complex so the rabbit hole is deep but there are a few basic things that can often help considerably. You might also consider alternatives to Ethernet that perform well, moca or powerline adapters.
We had this exact same problem while watching Hallmark via TVE. Have updated to the latest tvOS and latest Channels and for the last two days the freezing has not returned.
I am doing a CenturyLink DSL speed check on the PC that is my Channels server for recordings. The speed is maximum, 40 bits.
still, both recordings and live TV will freeze periodically.