I don't remember exactly when and what age Haaland went to Man City. But Haaland at Man City received tremendous support so he was able to perform well. Man City's players have good control that helps Haaland perform well. Meanwhile, Beier at Dortmund is indeed a good step and it is an improvement. I don't know for sure if Dortmund is doing business or if they are indeed aiming for the championship next season. But indeed Dortmund is always good at bringing in young players then they are made better and sell more expensive.