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.
I hope bayern to have competitors. I can't evne put borrusia in the same place as barcelona caused by this club was not even able to break the domination by munchen. No reason to call it same as barcelona. Bayern has been dominating the league for more than 1 decade and it doesn't even make sense to call bvb same as barcelona. We have some clubs are performing so well till this time and im so happy with it if the competition for the title race become even stricter than before.
Leverkusen is showing up to be another strongest contender to win the bundesliga this season. Stuttgart was even showing impressive performance till this time. The competition looked like even better compared with the previous season.
Dortmund was not barcelona who can prevent bayern to dominate the league anytime. It's far.