GrapheneOS

In this case, there is a trade-off between privacy and security. Using Google Play store is the most secure choice: Google is fairly strict about minimum API requirements for apps on its store, and it takes security seriously. They just don't take privacy seriously.

Personally, I've opted for using Play store for most apps unless they aren't available there or have some ridiculous subscription pricing, in which case I'll use Obtainium. My rationalisation is that I'm more worried about poor security exposing my personal & private data than I am about Google's invasion of my privacy when I use some of their services. It's a managed risk that I've decided works for me, but you may have a different risk profile.

Edit: oh I forgot to mention Accrescent. I have some apps installed from there and regularly check it for updates/new apps. GrapheneOS encourages using them as a store too.