Before Leverkusen became champions, only Munich and Dortmund were the title contenders. There were almost no other teams at the same level as them. Leipzig and Stuttgart were in second place behind them. And unfortunately Dortmund's performance was inconsistent in every season. They were only able to compete until the middle of the season and after that Munich would dominate the league until they became champions. Only in the 2022/2023 season did Dortmund play impressively and have the same points as Munich, unfortunately they lost on goal difference. But as far as I know Dortmund lost against Munich in the league match that season. This is different from Leverkusen who became the undisputed champion after drawing and winning against the Bundesliga king Bayern Munich.