Comment 3 for bug 1889010

According to the alsainfo.txt, the Capture source is not "Headset mic", so the headphone can't output sound.

 control.6 {
  iface MIXER
  name 'Capture Source'
  value 'Headphone Mic'
  comment {
   access 'read write'
   type ENUMERATED
   count 1
   item.0 'Headset Mic'
   item.1 'Headphone Mic'
   item.2 'Internal Mic'
  }
 }

Could you please remove the pulseaudio setting by running "rm -rf ~/.config/pulse/*", then reboot and check if the Capture Source is Headset Mic now?