F-Droid is the best way for open source apps, but also most APKs are available outside of Play Store via websites like https://www.apkmirror.com/. It's a bit of a risk to load apps like that, though.
It's a shame EV certs are so hard to get. APK signatures use certificates and we could use the already existing CA infrastructure to make app stores unnecessary but stuff didn't work out that way.
