You’re going to have to compromise on either privacy or security features. Privacy Guides and PrivSec have useful information related to this. The GrapheneOS App Store seems to be the best option, but they provide very few apps. From a strict security perspective, the next best option might be using the Google Play Store, but of course that comes with a privacy trade-off.
If you don’t want to use the Play Store, it seems like all the more privacy-respecting options might be less secure. Accrescent is a promising option but it’s still in development so I haven’t seen it officially recommended yet, not to mention it probably doesn’t have all the apps you’re looking for. Aside from that, Obtanium and Aurora Store are also popular options which allow you to install all sorts of apps.
There’s the famous F-Droid which is recommended against by both PrivSec and Privacy Guides due to security issues. If you had to use F-Droid, it seems like using the F-Droid Basic client and preferring the IzzyOnDroid repository over the official F-Droid repository might be the best way to do it, but there’s some debate over the pros and cons of this.