Dortmund started the season much better than Bayern Munich. They demolished Frankfurt 5-2 and improved their morale at a very high rate. Haaland was the player of the match that's for sure. He had 2 goals and 3 assists which was a really insane performance from the young lad.
Dortmund are keeping Haaland for this season too but I don't think that they will be able prevent him from leaving next summer.
Dortmund have always sold their best players but they always get the best performance from their players while they are there and get the maximum amount of money when they sell them.