I am currently implementing VoIP for an Android application. I used the ConnectionService abstract:

I only succeed to make it work buy letting the user doing this manual operation:

Which is really deceptive in term of user experience. After reading other threads I noticed that the only way of skipping this should be to use the Self managed approach.

The issue is that the documentation mentions:

Are a standalone calling app and don't want their calls to be integrated into the built-in phone app. Referred to as a self managed ConnectionService.

As you probably guessed, I would like to stay integrated with the built-ins phone app, which puts me in a situation where I am not sure what to do.

You can find a reproductible example: