For Mbappe, the best action take would be joining Real Madrid this summer and it seems like he will. Real Madrid are his dream team and Real Madrid want to sign him so bad too. PSG wouldn't be able to do anything to keep him for at least one more season I think. Whether they win the Champions League title this season or not, Mbappe wouldn't care about it and still would join Real Madrid. And considering his future, I think that it is better than staying at an unpredictable team like PSG. Real Madrid are a far more promising team than them.