How did TDK (and TDKR) change following Ledger’s death?

I rewatched The Batman recently after being a bit disappointed when it released. I was blown away this time…to the point that I don’t even understand how I ever had that opinion. I was so impressed with the quality of Paul Dano’s performance, I decided to rewatch TDK to compare it to Ledger’s Joker. I haven’t seen TDK front to back in a very long time and didn’t want to go off memory.

My god, Ledger makes that film something great. I can’t think of a better example of scene stealing. They really tapped into something special with him. I think the film is good without him, but not great. He is so damn magnetic from beginning to end. Few actors have hit me like that.

Question is, what was changed with TDK following his death? I’ve somehow never even considered it. I’ve been a bit underwhelmed by the final dialogue with the Joker and Batman since I first watched it. Not because it’s bad, it’s not, it’s just…not very satisfying. In hindsight, I’m guessing they thought they could get away with that because Joker was a certainty for the next film? Or maybe they had a different end in mind? Were they forced to change or drop anything with TDK after Ledger passed? What were the original plans for what became TDKR?