and this could happen to PSG because I don't doubt PSG's finances which might be able to make an offer to Haaland worth 100 million dollars will definitely make the player think deeper and possibly accept the offer from PSG.
Regarding Mbappe's departure, I am ready to see him go because he has provided many good achievements for PSG and it is time for Mbappe to look for another challenge with a bigger club to get the title he wants.
But if it was PSG I think Haaland would think about signing with them. You have mentioned yourself that Mbappe chose to leave PSG because he wanted to look for another challenge. Actually I don't think there is a difficult challenge at PSG for players like Mbappe or Haaland. If Haaland plays for PSG then he will do what Mbappe did where Haaland will win several Ligue 1 trophies and it will be difficult to compete in the Champions League.