calpurtmun i came to gos on p5 from sam s20 and I clearly remember screen downgrade which is still the case with p8. Pixel's hardware is forever behind.
As for black not really being black might be an issue of the user falsely expecting a "dark" theme to be "black" as I can not find an option in pixel settings for a "black" or "oled" theme, only dark. On the other hand some apps provide such options, and when chosen my p8 perfectly makes the true black where designed by those apps. So for this one it sounds more like a feature request that should be addressed to gos devs as an additional theme option.