The game is way to dark without HDR on, it used to do Auto HDR when launching the game on LG CX, now after the patch it’s not working anymore 
From what I am reading this game never had HDR for console.
I’ve got a PS4 Pro which can do HDR and it’s not using it. The biggest clue is that HDR TVs’ will actually switch and notify you they are in HDR mode. Mine does this when I play The Witcher 3. Also if there is no setting for the white balance and black levels, it’s a clue there is no HDR.
Now I’m not playing on the latest gen consoles so maybe they did get HDR but it was curious how hard it is to find out if they even have it. PS4 Pro does not for sure.
Do you have settings to adjust for HDR? Does your TV notify that you are in HDR mode when you play other games that absolutely have HDR support?
Yes my LG CX notifies me when HDR is on for a game, if I start Diablo 3 I get a HDR logo in top right corner. When I bought Diablo 2 Resurrected the HDR was working the same way HDR works for Diablo 3, the HDR logo was displayed. I can even go into the settings of the tv and it also says if HDR is active when having the game on. Somehow HDR stopped working when I updated to patch 2.4, don’t know why Anyone know how to solve this problem?
What console are you on and what settings ingame do you have for HDR?
It would be bad if all you had to do was check a box to re-enable HDR.
I am on Xbox Series X, I have HDR enabled on the console otherwise it would not work in Diablo 3 which it does work on. Is there HDR settings inside Diablo 2 R as well? I cannot see any