That's correct. I can't use it at all with my Apple TV or Playstation 5, because the screen immediately goes dark. I don't know how to describe this exactly, but say that the TV's regular RGB display goes from 1 to 100. I'd expect that HDR would make it go from -50 to 150, or something like that. Instead, on my Samsung, it goes from -50 to 50. No amount of control fiddling can make it get as bright as it does in non-HDR mode.

Our cheaper LG works beautifully with the same inputs. The Samsung? Nope. Everything looks like the finale of Game of Thrones, even when you're looking at a soccer game played on a sunny day at noon on the equator.