I have had this same issue on three different TVs, but it only happens in very dark scenes. I'm even seeing in dark scenes with new AppleTV+ content. I'm using the 4K HDR 60hz DV setting but I have tried the others and Dolby Vision looks so much better in all but the darkest scenes (for Dolby Vision content) so I keep at the highest setting.
I have a TCL 55R625 TV, so I do have to set the HDMI port to Enhanced (hdmi 2.0), and I have tried different cables of course, but the internal Netflix app on the TV plays Dolby Vision content correctly making me suspect there is an issue with Dolby Vision over HDMI in certain profiles (Dolby Vision profile 5 is what apple uses). It could be on the TV side and the Dolby Vision Tone Mapping Library that the TV is using or it could be the way the stream is processed. All I know is that I've tried everything I can think of at this point.