I agree with you that De Bruyne's entry into the team had a significant impact on the originality of Manchester City's attack. As an attacker, Haaland may find it difficult to miss De Bruyne's valuable pass. But it must be admitted that Manchester City have a history under Pep Guardiola showing their capacity to win under these circumstances. Guardiola is renowned for his ability to devise original methods and tactical mindset. He frequently compensated for the absence of key players by taking advantage of agile player rotations and effective tactical setups.
Guardiola is always trying to pick versatile players who can play in many positions and this is a very smart move as it will allow the team to rotate if necessary. But De Bruyne is more than just a good universal player, he is capable of creating scoring chances on his own and he has a great shot even from long range, the absence of such a player is always felt by the team.