When HDR is gone right, it looks incredible. i.e. Horizon Zero Dawn, AC:Odyssey.
When it's not, well... then you get RDR 2.
Now, the HDR in RDR 2 is very, very subjective. To me, the HDR in RDR 2 blows out the colors and they look more washed out, This is because the implementation pretty much brightens specific colors rather than objects and scenes. Therefore you loose a lot of detail, especially while in the snow areas because HDR blows our the white color. However... the positive is the game looks more "movie like" to me.
I have been keeping HDR off since I prefer to see the details in everything and the colors aren't blown or washed out, so the greens look more green, the shadows look more black, etc.... The SDR image contain a lot more of the details (since the HDR image is just the SDR image with a ton of brightness thrown on top).