From this, it looks like Apple have not resolved this issue when playing material on every brand of TV. I would not blame the C7, but Apple's implementation of the fix for this issue. The new OS for ATV will be released very shortly, so it will be interesting to see if it corrects this problem. As I imagine the Engineers have been completely tied up with working on the new OS, there may not have been the opportunity for Apple to release a fix separately - also, there may not be enough people reporting this to them to persuade them to push out a quick fix. If it ain't an iPhone problem, it doesn't get prioritysomething that I just noticed with the movie blade runner (original) on apple tv 4k. it plays perfect on my A9F and on my LG C7 the opening credits the background is not inky black but rather near black almost gray. changing the brightness on my LG from default 50 to about 47 improves it but I'm pretty sure everyone on here says to leave the default dolby vision brightness setting alone. i guess this might be an issue with LG? I always thought it was the way apple encoded this particular movie.
I stay at 50 for Brightness & for me it is the best setting. That seems to be the general consensus as well