Dortmund always creates its best players as happened to Erling Haaland who comes from Dortmund is also the best attacking player for now and next from Dortmund produces another good attacking player named Jude Bellingham and If Real Madrid want to have him then they have to move quickly so that when the transfer market opens at the beginning of the year he will not be bought by another club.
You're right Dortmund does admit that the players they sell to other clubs will have quite ideal roles. But not only that when Haaland showed his qualities as a Dortmund graduate, but it was also more than enough to consider other clubs who would definitely be eyeing the new seeds that Dortmund would sell. Then there is Ajax which is also famous as a club that has produced many shining players out there. Ajax dropouts are no less great. Ajax also has a special football school that has been established for a long time.