True, but it's a bit different for haaland caused by he was a finisher. Bellingham was attacking midfielder which was working even harder in helping its club to win the game. Haaland has proper finishing, and he was only wiating for his teammates to supply him the ball.
Haaland is a goal scorer and he did his goal scoring task well in all clubs he has played for. Dortmund do feel missing goals from Haaland as players they bought to replace Haaland did not bring similar total goals Haaland could score for them in a single season.
Jude Bellingham did not score many goals in Dortmund and he only improved it in the past season before leaving them to join Real Madrid. Jude has more connections with other players and he is an important chain for Dortmund operation than Haaland. They are both important players of Dortmund but Jude likely caused more problems for Dortmund in tactics than Haaland.
The difference between either of players are on how big the efforts are being made by them. Manchester city was not fully relying on haaland. Did you forget KDB, foden or alvarez?
Without Haaland, Manchester City still can score many goals because they could score many goals before Haaland came. Haaland helped them having many goals in the last season but they did not totally rely on Haaland to have goals. Foden, Alvarez, Marez, Silva and other attacking players in Manchester City could do it together very well.
Manchester city had so many talented players while real madrid have some. Ancelotti's decision to end Madrid's transfer journey earlier than other clubs is causing regret among many people.
How Real Madrid have less talented players than Manchester City? They are both big and rich clubs and Real Madrid still have many star players in Bernabeu. One Champions League is not enough to make Manchester City is a bigger or more successful club than Real Madrid.