Of course Dortmund will want to keep Haaland in the team, but will Haaland want that? That's the real question to ask. Haaland's release clause is low. You can find dozens of clubs willing to pay him this money. If Haaland doesn't want to leave then we can talk about different possibilities. However, in my opinion, he must feel closer to Real Madrid in Haaland. For some reason I feel like Real Madrid will sign him.
Haaland does not only need money but also hunt for titles. He will find a club which can help him having good opportunities to achieve such things simultaneously. Real Madrid are always such a perfect club. PSG, Manchester City are at next a little bit lower level. They are good now but does not have too big traditional history especially in Champions League. Barcelona are in bad period in last 20 years. Bayern might be another good choice for Haaland but I would prefer to bet that Haaland will move to another league so Bayern might not be his next destination.
Haaland would be making a good choice if he left Dortmund, let's look at Dortmund, they have little chance of being champions because we all know he became the champion that doesn't let anyone else be champion and that becomes complicated and frustrating for other teams and players , would not have much motivation for him to stay in the Bundesliga. The best option for him in my opinion would be if he went to Premier or Serie A or La Liga, but I hope he doesn't go to any club other than Real Madrid or Barcelona if he goes to Spain
Haaland seems to be one of biggest star or even super star players in an upcoming decade. He might have good ability to adapt to new club and to different tactics. I think he will get success in other clubs if he leaves Dortmund.
Because of this expected result, he might have good decision to leave Dortmund. In my opinion, he is different than other young players at his age. He has already been matured enough and does not need to grow up his skills to get a solid position in a team he is playing for. His skills are at world-class level already.