I wouldn't at all compare Bellingham with Haaland and also not confuse the recent success as a goal scorer with Bellingham being a full mode striker. It could be and it will still take some time to see whether Bellingham can keep going and scoring. But the biggest weapon Dortmund had was Haaland for a while and Bellingham was very good, but he never as decisive as he has now been for Real Madrid. It doesn't happen very often that a player decides a few games in a row in the last few minutes.
For Dortmund Bellingham scored a goal around every 8 games. For Real Madrid he scored 4 goals in 3 games. To me this is most likely more of an outlier than the expected standard.
Even Ancelotti is surprised by Bellingham's performance:
I'm not surprised by Bellingham's quality. What surprises me is that he has scored so many goals in the first few games. It's quite surprising for everybody and for him. He's a professional and he's very serious.
sourceWise Ancelotti does not raise expectations:
He can get to 15 goals because he did it with Dortmund.
This is a clear understatement because playing in La Liga for a dominant club, Bellingham can count on a clearly higher number of goals. In general, Real Madrid currently does not have a clear striker, but the group of players capable of scoring is quite large, this poses additional difficulties for their opponents.