Exactly.

If my device is compatible, does it automatically have access to Google Play and branding?

No. Access isn’t automatic. Google Play is a service operated by Google. Achieving compatibility is a prerequisite for obtaining access to the Google Play software and branding. After a device is qualified as an Android-compatible device, the device manufacturer should complete the contact form included in licensing Google Mobile Services to seek access to Google Play. We’ll be in contact if we can help you.

https://source.android.com/docs/setup/about/faqs

Google services are entirely missing from Android open source. The Google Play package is what contains the entirety of Google’s services.

Not sure if anyone remembers but back when cyanogenMod was the go-to, early versions had Google services included. Google sent a cease and desist notice and said it was a license violation. You cannot distribute it as part of the OS by default. The next release of cyanogenMod had it removed. Users had to flash the package if they wanted it.

Right but the topic was about google’s data harvesting and what I meant was that you can’t just grab any AOSP distribution if you want to minimize that, you need to pick one that replaces the parts that send data to google. LineageOS for example still phones google for quite a number of services.

As far as “easy to remove” goes, I think that’s kind of debatable if you want to do it in a way that’s sustainable long term considering the effort that goes into e.g. GrapheneOS or DivestOS.

Edit: here is a list of the kind of stuff you need to watch out for if you want to minimize the data sent to google

https://divestos.org/pages/network_connections

Yes but people are just sideloading GAPPS and escaping their ecosystem. Might even run custom launchers so you can’t experience their ads.