Are you just looking for a place to install apps?
Aurora Store is an open source alternative store front for Google Play. It anonimizes info using dummy Google accounts so that way you have some anonimity when acquiring apps.
Another alternative would be F-Droid which is a FOSS app store. From there you are opened up to a lot of open source apps you wouldn’t normally find.
You can also go to any site that hosts APKs (since that is all that is happening when you install an app, you’re installing the APK file), but those are kinda sketchy sometimes and no real way to confirm stuff. Or you can go to whatever Git repo that the app has maybe like GitHub and see the “releases” section.
Hope that helps!
Ah lol my bad, unfortunately I have also been looking for this but the only direction I’ve ever seen is that large financial insititutions are really only in work with the big guys and there isn’t much on the open source or alternative front besides Google and Apple.