I have a samsung oled g8 monitor connected with hdmi 2.1

I have read many very different settings about HDR on this monitor, basically the two settings that involve HDR are:

Peak Brightness
HDR10 Gaming
GameHDR (HGiG)

I always have Peak Brightness on high.

If I leave HDR10 Gaming activated, but leave GameHDR disabled, I can get 1000 nits when calibrating HDR in Windows 11. If I activate both, I only get HDR 400 (even with Peak Brightness activated on high)

And the funny thing is that if I deactivate both options (leaving Peak Brightness on high) I get about 2700 nits of brightness when calibrating in Windows.

Can anyone who has this monitor guide me on what the best HDR configuration is?

As a curiosity, in shadow of tomb raider, if I do not activate GameHDR (HGiG) I cannot correctly configure HDR in the game interface. Maybe the game only supports HDR400?

Thank you.