A fun grassroots activity may be to give a one star rating to all the apps Google has replaced with a closed source version. Such as the dialer, calculator, calendar, camera, etc. If done in great numbers it may give a strong signal.
Nearly every big manufacturer replaces apps. Samsung, Xiaomi, you name it.
Their modified Android OSes are 10x heavier than they should be, and those manufacturers don’t really care if users have a good experience.
So, another grassroots activity is to not go on Google Play, but rather, on F-droid, and install open-source, well-designed apps.