How big and which audio format (mp3, wav, ogg, m4a, ...)?
Exactly.
Set the Player.Source before Player.Start (e.g. in the Screen.Ibitialize even).
And then use a Clock: If Player.IsPlaying then Clock.TimerEnabled = false.
Note:
Search for "radio app" and "streaming" regarding Doze mode issues on Android 6+ devices.