Manchester City will be the strongest team if they manage to get Mbappe because the quality that Mbappe has will encourage them to become a team that has goal-hungry front players. However, Manchester City efforts to get Mbappe are certainly not easy because Real Madrid will be at the forefront of getting Mbappe. But everything could change if Mbappe is more interested in playing in the Premier League then Manchester City or Liverpool will be his goal.
It would be great to watch Mbappe at Manchester City. I'm sure every Manchester City fan would want that. But we know that Mbappe had some problems before when he was in the same team with Neymar and Messi. He might have similar problems playing with Haaland. There are younger players at Real Madrid, so he can gain respect from them. And we can see him as a dominant character at Real Madrid. But when he plays with Haaland he might not be the dominant character. I think he will be more successful at Real Madrid.
The rumors has been circulating that Mbappe may likely move to Spain to play for Real Madrid next season but Mbappe is yet to make it public for far concerning his future so it is open for any good team to seek for his signature even Manchester City because they have a great team and Mbappe will fit in the team even though Haaland is currently playing with Manchester City but his presence may not affect the performance of the French player Mbappe. Personally I don't think Mbappe will let his pay issues with his other team mates affect his choice of club but he is likely keen on joining Real Madrid which has been one of the strongest bidders for his signature and the number of players and the position he's to occupy in the Real Madrid team is one of the reasons why he's likely going to choose the Spanish giants over other teams.