Sorry to revive this old topic but I couldn’t find a more recent one and it suits perfectly.
Why is the audio preparation only available in the phone call mode? Couldn’t you just play a silent beep, delay, and then output the directions?
Unfortunately I have similar problems with my Avantree Apico earbud, however using the phone call mode is not the optimal solution because:
The headset plays an annoying sound before and after each navigation announcement which is even louder than the announcement itself. “Increase voice volume” is already checked but it’s still not loud enough. Can I make it louder somehow? If I change the volume on the phone this stupid “call notification” sound gets louder as well.
Voice quality is significantly worse when using HFP instead of A2DP. Not really a problem for navigation directions but still notable.