Android may be technically 'open source' but it is not a collaborative project. It is completely controlled by Google, who are reducing the frequency of their source code releases and gradually making it more difficult for third-party Android forks to survive by convincing app vendors to make their apps refuse work on non-'certified' Google Android installations.
Alternative phone operating systems are the way to go if you really want to de-Google. Lots of them can run Android apps as well as the Android forks for now, and their own app libraries are growing rapidly as developers get tired of Google's shenanigans.
Android may be technically 'open source' but it is not a collaborative project. It is completely controlled by Google, who are reducing the frequency of their source code releases and gradually making it more difficult for third-party Android forks to survive by convincing app vendors to make their apps refuse work on non-'certified' Google Android installations.
Alternative phone operating systems are the way to go if you really want to de-Google. Lots of them can run Android apps as well as the Android forks for now, and their own app libraries are growing rapidly as developers get tired of Google's shenanigans.