You can get the highest count using Django's .latest() method. Though documented for dates, it also works on strings and integers.
This should get you the Action with the highest to_player count:
# combined the filters, no need to separate into two steps
v = Action.objects.filter(game=1, step=2, type=3)
v = v.annotate(count=Count('to_player'))
v = v.latest('count') # will return Action with the highest count