Dortmund's goal is to buy more and more young players and earn money from selling these players and that's their first priority otherwise they could keep the superstar palyer they had before.
Also, I think Dortmund is a great player supplier for Bayern Munich and there are many players from Dortmund who left this team for Bayern Munich because Dortmund could earn a good amount of money.
That's right, Dormunt maintains its existence as an elite Bundesliga club by transferring young players and releasing them with star player status. Dortmund doesn't seem to care even if they have to let them go to eternal rival club Bayern Munchen, they only care about the highest offer. However, on the other hand, Dortmund can be said to have always been successful in this way, and is always able to compete closely with Munchen in the standings every season. Maybe I have already said it, the transfer policy of the two clubs from another perspective, provides indirect benefits for the German national team, we know that these two clubs send more players to strengthen the German squad than other clubs in Europe. In terms of chemistry, a culture of play and adaptation has been formed at club level, so that they appear more solid when playing at national team level.