My HDR recommendation for LG C9 TV and NVIDIA graphics card (not what you'd expect)

[Ymetro]

Tested so many settings in game, in the desktop and on the TV; this is my result:

Set TV in Game console mode (change the icon via the home screen editor) and black level in the Display Options menu to low. PC mode just seems to through unprocessed output at the screen pixels, losing some color data on what the pixels expect to receive.
Also use Dynamic Tone Mapping in the ON setting, when HDR is enabled, as HGIG is a nice protocol, but is not making it pop enough.

In NVIDIA Control panel ⇒ monitor ⇒ change resolution:
Set to your preferred resolution and refresh rate (I use 2560 x 1440 120Hz, but you could set it to 60Hz for a lower tier graphics card and limit the fps in game to 30 or 60 fps)

Below NVIDIA-color settings (I translate from Dutch, so exact wording being used in English escapes me atm), set the following to:
Desktop color depth: Highest (32-bit)
Color depth output: 10 bpc, because the OLED panel only supports up to 10 bit
Color format output: YCbCr422
Dynamic range output: Limited (remember to set the TV's black level to low)

Enable AutoHDR in Windows Settings or by pressing Win + Alt + B.
The TV will confirm the action with an HDR label in the right top corner of the screen.

Set DTR to ON.

Then in game set the HDR setting below the Display tab to: OFF !!!
I know, it seems weird advice, but it looks the best for me. No, or less, dithering in dark regions. And no washed out items and menu's.

Hope it helps.

Enjoy the colors and black levels! (They aren't that black, though 😿)

Addition: There is a fix for the blacks not being black enough:
Set the LG C9 TV's below Display ⇒ Additional Settings ⇒ Fine-tune Dark Areas to (minus) -30 .
Looks HDR-ish to me. 😉
But then again: when not playing, you'd better reset that to zero (0).