Borussia Dortmund is known to be selling their best players in almost all the summer transfer windows and that is why Bayern Munich will continue to dominate the German Bundesliga for more seasons to come.
Jadon Sancho was sold last two summer before Erling Haaland was sold to Manchester City last summer and now Jude Bellingham has left for Real Madrid. I think the club's transfer strategy isn't concerned by the success of the team rather they're more concerned by how much they make as gains when they sell these players. They might also be lucky raise another great player before the end of next season and still sell him at the end of the season
Dortmund always make a lot of profit in the transfer window by selling their players. Jude Bellingham has set a new record for Dortmund where he is the second player to be sold by Dortmund for a fairly high price. Sales of players are too synonymous with Dortmund because they have done it repeatedly in every season, making Dortmund unable to compete in the bundesliga to win the bundesliga trophy. For Bayern Munich, they continue to make pretty good changes in improving the quality of their performance for next season. I think Bayern Munich will always be at the forefront of winning the Bundesliga trophy because in the Bundesliga only Bayern Munich are aggressively bringing in good quality players compared to other teams.