I agree with you that bringing Killyan Mbappe to Manchester City will only be possible if Real Madrid can't find a chance for Killyan Mbappe's signing but Honestly I am pretty pretty 100% sure that real Madrid will sign Killyan Mbappe in this summer transfer window Because all sources of news have written that the deal agreement between Real Madrid and Killyan Mbappe has already been finalized. just a fake rumor. It was only meant to create suspense and nothing else. 
 
So i am 100% sure that Killyan Mbappe will be a player for Real Madrid next season. There is nothing like that. He likes Real Madrid. It has been his dream since childhood. It is a matter of passion. If he liked money, why did he not go to Saudi Arabia? Rather, it is a fake rumor that he wants to go to Manchester City because Manchester City is ready to pay a big wage.