How to connect bluetooth a2dp?

Question

Bluetooth

Good day to all.
The scheme is as follows, there is a telephone, there is a micro-pc (raspberry pi), there are ordinary wired headphones. You need to establish a bluetooth connection between the phone and the micro-pc so that the phone recognizes the micro-pc as headphones. And in fact, the micro-pc already broadcast the audio stream to ordinary wired headphones. Here.
After googling, a lot of things were done, and in particular, the scheme was implemented. But now I can’t debug everything so that the sound is good. The problem is that the sound crackles, breaks and all that sort of thing. It feels like the bass is somehow cut. There is a delay in the form of 5 seconds (when you pause on the phone, the music will actually stop sounding in the headphones only after 5 seconds). In short, something is wrong. Everything works through pulseaudio. What can be done, set up and configured so that everything works and is like in machines connected and everything is perfect.
Thanks in advance for your reply