I have a rpi 4 with a hifiberry amp2 and have installed max2play on it with a LMS.
My idea was to use shairtune2 in the LMS for AirPlay but it is not working.
When squeezelite is activated in start up, it automacially start shairport at the same time. I have tried to stop the shairport plugin, but it is not working I have to kill it. And even if the autostart of shairport is inchecked, it stil autostart togheter with squeezelite when the device restarts.
shairtunes2 uses shairport-sync. Check if the switch between airplay and squeezeplayback works, it should be set up already to work the way you want it.