Forget the Play Store: I built a self-hosted app updater on Android

Obtainium update-ium are the magic words ...
How-To Geek

4 safe ways to download Android apps without using the Google Play Store

To download and install an app on Android, you need to prep your device. Forgoing the Play Store bypasses Google's security ...

Your Android phone can install apps outside the Play Store – here's how

While the Play Store is the go-to place for installing apps, Android devices also support sideloading them. Here are two ways to sideload apps on your Android.
The Droid Guy

How To Download and Install Google Play Store on Any Android Device

The Google Play Store comes pre-installed on most Android phones, but there are situations where it’s missing, disabled, or broken. Devices from China, Amazon Fire tablets, phones running custom ROMs, ...