And even though there is no Haaland, Dortmund can still compete with the top big teams in the Bundesliga like Bayern Munich, which means that Dortmund really have the ability to train their players to be better and they almost won the Bundesliga title. It's just that Dortmund had a draw in their last match so they had to continue to die to become champions, but for next season I'm sure Dortmund will again make better competition from the start of the season to the end of the season.
Without Haaland they were able to nearly get the trophy and only lost it in the last match but in this summer, they just sold Bellingham to Real Madrid. This transfer is a second highest transfer in history of Dortmund only after the transfer of Dembele to Barcelona years ago.
Dortmund has that transfer strategy to sell their star players at highest price when they can. They also want to maintain their salary ceiling and don't want to break it for their star players anytime they have to convince their star players to prolong or sign new contracts. In finance, it is a very smart and safe strategy but in sports, it did not help them to win titles. With this strategy, they will not win Bundesliga in many more seasons.
This shows why Dortmund could not beat Bayern Munich in the last 11 years. They sold most of their best players to Bayern Munich and we see the reasons. Selling best players already reduce their squad power but selling those players directly to their direct competitor is worse. They became weaker and their competitor became stronger, no chance to win Bundesliga.