I also have the same problem with 2020 Q8DT, way too dark with HDR content. Worked with SAMSUNG Support Tech and there apparently is nothing wrong that they see and that really it is the NETFLIX or most other providers formatting. There are no settings at all that really do anything to fix this and we (with SAMSUNG) looked at everyone of them. It may not be just a SAMSUNG issue - and if you look at other manufacturers complaints, you will find the same thing....though perhaps some super bright OLED may be quite a bit better. I have asked that SAMSUNG simply have an option to turn-off HDR because every other format on this TV, HD, 4K, UHD, SDR ect. looks absolutey great. They said that will elevate that, but who knows, as thousands of others have the exact problem....I also have loaded 1403.1 which does not fix this problem in any way. Good luck and after spending thousands for a TV, really the TV manufactures needs to strongly complain about the various HDR formats that film producers are using whichare not all compatable with most HDR TV manufacters today - it is a real mess IMO...but SAMSUNG should just have a software setting to turn this HDR OFF...seems so simple but they will not yet fix this in some way.
