I tried to use the A2DP_Sink_Example from Espressif. But there was one big drawback - the volume control over my smartphone didn't work. Instead I got disturbed sound from the ESP32 if I put the volume on my smartphone a little bit higher.
I fixed the code in the Espressif-example in order to control the volume over the smartphone once again properly.
Watch my YouTube video on this: https://youtu.be/4a10Tl5eR30