The Pixel version of Android has some great features, such as adaptive battery, now playing, and others. I understand that it is proprietary, but so is GPS. So theoretically, it could be an optional addon?
Thanks for the insight.
GMS can be used on GOS because the apps are distributed as is. Google does not and cannot distribute files containing these features as addon to include in your project because they are part of the OS. These kind of things are precisely why projects are made opensource. What you ask for cannot be done and wouldn't be allowed by Google even if it could.