It's hard to imagine how chelsea would able to win against dortmund.
Not sure why you thought so. Chelsea have better history in Champions League than Dortmund. They won 2 Champions League and in many seasons, they went to quarter final, semi final and final matches. With Dortmund, they only won 1 Champions League against Juventus in 1990s and in the past 20 years, they did not have better record in Champions League than Chelsea.
As far as i know if chelsea has so many problems. Anyway, dortmund keeps getting more and more good results in bundesliga which has proven how strong dortmund. I'm thinking about the match will end with draw as the final result. Dortmund will not let chelsea win. Dortmund shall win against chelsea but chelsea can also come with new strength. Chelsea can be considered a new team after so many players got replaced. Im thinking about pick dortmund over chelsea right now.
Chelsea can play well in Champions League especially in knock out matches. Because their players can feel unhappy in Premier League and are not ready to fully fight there but in Champions League, they know they mostly have only one chance to win it in their career. So if they can, they will fight best to win one Champions League.
Dortmund has been fully prepared against chelsea. The problem is moukoko will not be playing against chelsea. He will come back to play against hertha.
Chelsea have more quality players than Dortmund and Dortmund lost their best player, Haaland to Manchester City in the last summer. So far Dortmund have yet been able to successfully replace Haaland by another striker. Moukoko is far from a top notch striker like Haaland.