Insular seems similar to shelter, also on f-droid.

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.

really necessary?

no but there are some settings in about:config you might want to change

this is a good video (easier to follow if you are on linux) that shows installation of a profile with all the settings already in it

One of the best is Iceland

https://lemmy.world/post/2338283

There isn’t really an alternetive launcher but you could download a firewall app like NetGuard and block every connection exept g.whatsapp.net

You can help Aurora by making more accounts to combat rate limmiting

but apart from that I don’t really know how to help - almost all my apps are from F-droid

For me Aurora still kind of works, although I often get the “Rate Limmited Account” message.

You can set Aurora as the handler of Play Store links in settings, that’s not affected by rate limmiting, if that stops working just download apk files directly from websites

Default OSs are very invasive. Windows, Mac and iOS are constantly spying on everything you do and stock Android is only as private as the apps it comes with which include things like Google Play Services - an app so baked into the system it can only be disabled through adb/root

If you want to read into this - Louis Rossmann made a video on this and this is the paper he mentioned.

possible for the average person who doesn’t feel comfortable messing with installing operating systems to have any privacy?

Yes, depends on how far you are willing to take it.

Replace default apps with FOSS (F-droid)

Delete or disable defaut apps through developer options/adb

Limit the number of permissions you give to apps (your calculator shouldn’t have access to internet or your camera)

Don’t install apps that you don’t trust/need

Block app’s access to the internet with a firewall

Check out r/degoogle on Reddit for many useful resources

For Windows/iOS, etc.: change settings to be more private: give less permissions and turn off telemetry wherever possible.

If you think that’s not enough, consider dual booting a Linux distro like Linux Mint Cinnamon (easy to set up and very beginer-friendly). If you do that you can learn Linux and keep your private data there instead of on Windows/iOS