Sound quality is worse when transmitting and receiving over Bluetooth, when I use the AirPods for calls on the MacBook I switch to the microphone on the MacBook, they will hear me better and I will hear them better since the AirPods will use all the bandwidth for outputting audio only.
This is certainly the opposite of my experience. The sound quality from someone speaking via their MacBook microphone is noticeably worse than someone speaking via their AirPods microphone.
Are you sure this is a bandwidth issue?
I always assumed it was more about the position and size of the microphone.