Android is not developed by Google. It’s open source but Google adds a lot of stuff on top. There are ways to minimise what apps can spy on you: gboard, keep notes, calendar, calculator, gmail - all can be swapped for better and more privacy respecting apps from F-droid. You can also disable Google and other system (vendor) apps through adb. Some OSs if you don’t want to do that are Lineage OS and Calyx OS.
Insular seems similar to shelter, also on f-droid.