Don't just focus on Leverkusen as Munich competitor remember Bundesliga still has Dortmund, indeed this season Dortmund has not shown significant improvement but we don't know what they will do next season and usually Dortmund brings something different every season for example new players who shine. You know Sehrou Guirassy is one of Dortmund players who is attracting attention in the Bundesliga he is only 5 goals behind Harry Kane who knows next season he can take Dortmund to a better place.
Personally, I think Bayern Munich will continue their dominance in the Bundesliga. In the past few years, we have seen that Bayern Munich has dominated the Bundesliga every season. Despite Dortmund's strong squad, this team has not been able to compete for the title. Suddenly, Leverkusen has broken Munich's dominance. However, this season, Bayern Munich has regained the top spot in the table. Munich will continue this trend next season if Leverkusen and Dortmund do not strengthen their squads. It is also unlikely that Leverkusen and Dortmund will strengthen their squads by building up big funds.