greenwood I like the idea of the [F-Droid] store and automatic updates and everything that just seems to work.
The Google Play store is likewise convenient with respect to updates, and has many more apps!
If one is attracted to F-Droid over Play, presumably one dislikes some features of Play and prefers some features of F-Droid, which is fine. But there are ways that F-Droid's security is significantly less strong than that of Google Play. Security is complicated, so any discussion of the how and why will be long and complicated.
The simple way to be secure would be to use only apps from the GrapheneOS "App Store" app (which also handles updates well).
If one is looking for a simple and secure and anonymous solution with lots of apps, the answer is clear: there isn't one.