i came here to say this fix works
the name of the file needs to be __init__.py
with the underscore
content of the file:
import aqt.sound
from aqt import mw, gui_hooks
from aqt.sound import SimpleMplayerSlaveModePlayer, av_player
def myfunc():
av_player.players[0].shutdown()
aqt.sound.mpvManager = None
mplayer = SimpleMplayerSlaveModePlayer(mw.taskman, mw.col.media.dir())
av_player.players[0] = mplayer
gui_hooks.profile_did_open.append(myfunc)