Try out Aurora Store. Just started testing it. Looks and works similar to play store but without adds. You can login with should not use your main google account.
When I'm installing F-Droid I get a security alert about it being developed for a previous android version and that it doesn't include latest privacy updates. How legit is that? I'm downloading the apk throught their official website https://f-droid.org/
Not exactly. It's possible to make an app run on older versions (select lower minSdk) and yet take advantage of newer features (select higher targetSdk). This one can be easily be fixed by the F-Droid developers like almost all other developers have already.
Droidify is amazing, I'd totally recommend that over the official F-Droid client any time. 👍