Dortmund and Leverkusen won't pose a serious threat to Bayern Munich this season, as neither team is yet on par with Bayern Munich in terms of strength. However, if we look at the details, Dortmund might be better than Leverkusen this season, although Dortmund won't be able to break Bayern Munich's dominance this season, as Munich remains quite solid with the depth of their squad. I wouldn't expect anything less from Leverkusen or Dortmund this season, as Munich will never neglect any opportunity to win this season.
When you do this analysis well, you know that both teams you mentioned are not even close to treating Bayern Munich because Dortmund is not doing anything different, and also Leverkusen, so we think Bayern Munich will still be defending this season, and I don't think Dortmund will be better than Leverkusen because there is a lot of difference in how they are playing, so I will choose Leverkusen over Dortmund. And Bayern Munich is ready to go to any extent to also win the Bundesliga, so we should not even assume that any other person is going to win, so all we can do is to expect something different. We know the winners already.