Dortmund is considered as weaker than Chelsea. They don't have a strong striker like Haaland and it is a disadvantage for them. Chelsea have better players than Dortmund and they will be a favorite team for gamblers. Anyway, in football, surprise is the most interesting thing and we can wait for surprise from Dortmund. It is supported by unstable performance of Chelsea in this season.
The truth is that Dortmund is very weak this season, when they had Haaland in the last season they were better in performance. Chelsea is more better than Dortmund in performance , but football is full of surprises, let's wait and see what the end of it will be.