I mean it looks like Haaland is planning a 2 or 3-year journey at Manchester City for now. He can be open to play for different teams later on and Real Madrid might go for him if they don't sign Mbappe until then.
I think Madrid should get Haaland instead of Mbappe. after previously Mbappe rejected Madrid's offer and that angered quite a few fans. we can see the response in the media some time ago. not good enough for Madrid to sign Mbappe.
Rumors regarding Haaland circulating are still confusing. but Man City obviously won't let Haaland go. he's a valuable asset to Man City. but if it's an attractive business for Man City, it's possible that an agreement can be made between Man City and Madrid.
My personal opinion is if Real Madrid does decide to get mbappe, it might not be the best decision. Because he is just an egocentric young kid who does not have any idea how to respect others and even his own teammates. But on the other hand, Haaland has shown a lot more maturity and actually played well with his team. So my opinion is that it will be better if Real Madrid does decide to go with Haaland. And remember mbappe had a chance to play for Real Madrid. Real Madrid even offered somewhere around 200 million for him. But he still chose the money that PSG was giving him.