Dortmund doesn't really want to win a title either in the Bundesliga or in the Champions League because Dortmund's goal is only to train its talented players so they can sell at high prices to elite European clubs. If Dortmund wants to win the title, it might happen because Dortmund has talented players in it, so if they are able to compete strongly and pursue their ambition to win the title, Dortmund will definitely be Bayern Munich's strongest rival.
Unfortunately, Dortmund only thinks about business without thinking about the careers of its players so they can win trophies, that's why many Dortmund players don't want to stay at Dortmund for long because Every player definitely wants the title of champion at the club he plays.
BVB could actually be Bayern's arch rival for years, just like Real Madrid-Barcelona in La Liga.
However, unfortunately this philosophy is not like the top teams which keep their best players in the elite Bundesliga teams. Many talented players have moved to other teams, perhaps this is all due to business reasons, apart from stabilizing the club's finances. But in my opinion, as long as BVB cannot retain talented young players for the team's future, it will be difficult to become Bundesliga champions, let alone winning the UCL league, it will not be possible.
Actually, looking at the current conditions, this discussion is always repeated but in the end it always comes to the same conclusion where when Dortmund sells their players, it is indeed their way of financial gain.
This has always been the absolute reason, they want to win but in the end they don't like to take risks and prefer the path where they will only use the players for their financial benefits because indeed in several seasons it seems to hint that their target is not the trophy but the financial balance of the club.