If not Leverkusen, maybe Stuttgart will be a contender for the Bundesliga title this season because they are performing well and they can even finish in 2nd place, although perhaps towards the end of the season Bayern Munich's performance will no longer be as optimal and it might be a different story if there is no Leverkusen name at the top of the standings.
It's hard to predict. The Club's condition will still be affected by the transfer market. Maybe Bayern will remain in the top flight with Dortmund, Leipzig. Then about Stuttgart and Leverkusen they are the teams that make a surprise. Judging from last season there was a big change, Stuttgarat is a team in the Relegation Zone, but they were able to survive and this season we have seen that. Then Union Berlin last season was quite competitive, this season they dropped quite far at the bottom of the rankings. The German league seems to be too competitive for dominance of the top 5 teams, so it is difficult to determine who will continue to perform great and end up at the top.
Talking about the top flight, I am still very confident that Bayern Munich will still occupy the top flight at least in the top 4 or 5 of the standings, but to become champions, as you said, is something that is very difficult to predict. This season is probably the first time in several seasons that I can't say that Bayern Munich will be champions, because in previous seasons, I was always confident that Bayern Munich would become champions and that really happened.
Next season the competition will be very fierce, it is not easy to determine who will dominate, because now there are several names of clubs that can compete at the top apart from Bayern Munich and Borussia Dortmund, so it is not easy for us to predict who will be better than them next season. However, I welcome this competition because with very tight competition it will make the league even more interesting and as a football fan I am happy with that.