PulseAudio: switch Bluez card A2DP Audio Profile off and on and set it as default sink to disable lags.

bluez_lag_off.sh

#!/bin/bash

# Tested on Linux Mint 18.3 / Ubuntu 16.04 with PulseAudio 8.0.
# No need for superuser.
# You can map it to keyboard shortcut and press when bluetooth audio starts lagging.
# Reference:
# https://askubuntu.com/a/171165/373130
# https://askubuntu.com/a/72076/373130
      
BLUEZCARD=`pactl list cards short | grep bluez | awk '{print $1}'`
pactl set-card-profile $BLUEZCARD off
pactl set-card-profile $BLUEZCARD a2dp_sink

# NOTE: You may have different profile names, for list of it execute:
#pactl list cards
# and look for:
# Card with name bluez: Ports: headset-output: Part of profile(s):

BLUEZSINK=`pactl list sinks short | grep bluez | awk '{print $1}'`
pactl set-default-sink $BLUEZSINK

# NOTE: You may also need to move active input sinks:
#pacmd list-sink-inputs
# and iterate through its indexes:
#pacmd move-sink-input 5 $BLUEZSINK
# but in my case input sinks are moved automatically