For simplification let’s assume that our Android app is connected to Firebase. See doc.
We are using Firebase AppDistribution to publish Alpha(UAT) builds in most cases.
Some projects may not have a testing environment/app setup but this guide should be valid for PROD release as well. Firebase AppDistribution supports publishing APKs and AABs. AAB publishing requires additional
steps and permissions (admin/owner) so APK is used as Alpha(UAT) build is concerned.
Create a tester group in Firebase console and add testers if there are none.

Add com.google.firebase.appdistribution dependency to a project
Add gradle plugin dependency for app (<project>/<app-module>/build.gradle.kts ) and project (<project>/build.gradle.kts) files

App module gradle file

Project gradle file
Configure AppDistribution gradle plugin

Can be added to app, project gradle or into each build variant section
TEST_GROUP_ENV_ARG is name of your test groupFIREBASE_TOKEN variable (will be shown later, section 2).We are using https://github.com/Triple-T/gradle-play-publisher to publish test builds into Google play internal track.
You can see full configuration guide here but some steps requires admin/owner permissions.
Play publish plugin supports publishing APKs and AABs. AAB file is used for Google play since we are no longer uploading APKs for releases. AAB publishing may require some additional steps.
Add com.github.triplet.play dependency to a project
Add gradle plugin dependency for app (<project>/<app-module>/build.gradle.kts ) and project (<project>/build.gradle.kts) files

App module gradle file

Project gradle file
Configure Play publish gradle plugin

app module gradle file
ANDROID_PUBLISHER_CREDENTIALS variable is used (will be shown later) as including your service account file into VCS could be seen as security risk.internal