How to sort parent objects by children?

Question

Django

There are 2 models:

class Chat(models.Model):
    members = models.ManyToManyField(User, verbose_name="Участник", related_name='members')


class Message(models.Model):
    author = models.ForeignKey(User, verbose_name="Отправитель", on_delete=models.CASCADE)
    recipient = models.ForeignKey(Chat, related_name='received_messages', verbose_name="Получатель", 
on_delete=models.CASCADE)

Message is bound to chat. And I need to sort the chat under the latest message.
Right now my sorting works by chat creation time
messages = Chat.objects.order_by('-pk').filter(members=request.user)

Answer 1

Add the time of sending to the message,
and as a result, the sorting will be like this:
Chat.objects.order_by('received_messages__timestamp')
If timestamp is a field in the Message of type models.DateTimeField
PS A minus at the beginning is possible

Answer 2

1. add the time of the last message via annotate https://docs.djangoproject.com/en/3.1/ref/models/q... and sort by it
2. Chat must have members, not Message? And then so in each message the list of participants is duplicated