Googlebooks are here, featuring high-quality OLED displays that promise full P3 coverage and accurate colors. The reality is currently different, however: the Googlebook operating system only uses the small sRGB color space, and color accuracy also leaves something to be desired.
Like the other person said, you should really switch to another ROM like Graphene or Lineage. (Graphene has a bit of a learning curve for newer users IMO)