Dortmund will only be in the top four next season, but there's little belief that Dortmund might finish second next season if other teams don't perform significantly better. Since there aren't many teams in the Bundesliga with the same strength as Bayern Munich, Dortmund could have a chance to finish second next season. However, teams like Leipzig and several others could pose serious obstacles for Dortmund and Bayern Munich next season.
Dortmund will not easily get a position in top four as their quality has dropped a lot since their latest peak with a runner up in Bundesliga and in Champions League two seasons ago. They seem to struggle to find new young players with good quality, professionalism and mentality to grow up and contribute for their clubs like they succeeded with Jude, Haaland, Sancho seasons ago.
Dortmund, Leverkusen, and Leipzig will likely be the top contenders after Bayern Munich. There won't be many surprises. I think those four teams will compete fiercely, but Munich's dominance will certainly continue. I haven't been following the Bundesliga transfer window closely. However, I noticed that Leverkusen has lost the most key players. So I think Leverkusen will struggle under Ten Hag. But this is just a statistical analysis; the ball is round, so there could still be plenty of surprises.
They will be not contenders against Bayern Munich but contenders with each other for positions in top four of the league and chase for a runner up position in Bundesliga. A first position, a title belongs to Bayern Munich as after Xabi Alonso leaving Bayer Leverkusen, and many star players are leaving Bayer Leverkusen and other clubs, this league will be under Bayern Munich domination in this season.