Enable Unity Audio to run in the background on Android

I've finished a mood music app in Unity that plays sounds and music to create ambiance for Dungeons and Dragons.

A previous developer implemented a service that enables audio to play to native android. This enabled the music and sounds to run when the app loses focus.

The app was working and was ready for release.

The app stopped working when Google required API 31.
The app uploads to the google play store, but there is no sound.

I need someone who understands android plugins, native android audio and Unity to fix the plugin or Unity...or whatever is broken.

I will need ongoing support when google requires higher API's.

I found this plugin on the Unity Asset Store:
https://assetstore.unity.com/packages/tools/audio/android-background-music-player-200748#reviews
The plugin developer was helping me with the app but he ran out of time.