I have a Samsung OLED G8 monitor and I am extremely confused about the settings for HDR. I understand that for bright games HDR 400 true black is better and HDR 1000 for dark scenes.

Regardless of how I configure the monitor I cannot get HDR 1000, I can only exceed 400 nits by deactivating HDR10 and Game HDR (peak brightness on high) but then, both in the windows calibration tool and in the game's hdr calibration (forza horizon 5) it recognizes it as more than 2000 nits, which I find very strange.

Also, if I set it to HDR 400 by enabling both options (HDR10 , game hdr) and with peak brightness on high, it detects it as HDR 400 (which is expected, since game HDR reduces the brightness to 400) but then, in the in-game calibration (forza horizon 5) I can never see the calibration image, even if I put it at the top left of the calibration bar, as if HDR is broken.

Can someone help me understand all this? I have no experience in HDR, thanks.