This used to happen on my Samsung 4K TV. I reset the device and it didn't help. I have a high quality HDMI cable. What seems to have fixed the issue is turning on "HDMI UHD Color" for the input associated with my ATV4K (probably called something else depending on the TV manufacturer). Another thing to note is that you should have the ATV at 4K SDR, 4:4:4 Chroma, and set it to match frame rate and dynamic range. Over time, the problem should go away. If this doesn't work, look for a PC mode for the input. Some report this as a solution. This issue seems to affect some, but not all. It's a shame when it happens because the ATV4K is fantastic.
In addition to the above I also close any open apps on the ATV . So far this strategy has reduced but not eliminated the black screen problem.
Find a post useful, please click on "Like" to give the author recognition or mark as an accepted solution.
I have experienced the black screen, as described here. Seems to happen on some channels only. Regular broadcast channels seem unaffected.
If you find a post useful, please give the author a "Like"
After the latest TVOS update. My screen ATV settings reverted back. I seem to be getting a solid two hrs use before black screen.
I then just close the app and reopen the app. When I watch PIK I start by closing and opening the app too.
All in all a manageable annoyance for me. PIK is still a great deal and nicer on a ATV.