The A8H has an excellent HDR color gamut. It has superb coverage of the commonly used DCI P3 color gamut, and its coverage of the wider Rec 2020 is decent. The EOTF follows the PQ curve almost perfectly, with only some brightening in darker scenes to avoid crushing. And like other Sony OLED TVs, it has a very sharp roll-off towards the TV’s peak brightness. The ‘Game’ mode EOTF is nearly identical, which you can see here.
If you find HDR content too dim, you can make it brighter by setting Advanced Contrast Enhancer to ‘High’, Peak Brightness to ‘High’, and Brightness to maximum. These settings will result in this EOTF. You can also increase the Gamma slider and the Black Level for an even brighter image, although they weren’t used for our EOTF measurement.