PSG can have guirassy as a good striker who can be bought. He is cheap and good, mbappe often played as a striker. and psg needs his replacement. There was no vengeance from PSG to the real madrid as mbappe left from team under his own intention and none forced him to do that.
I'm not so sure Vinicius Jr will lose his main place at Madrid if Kylian Mbappe agrees to join Madrid next season, possibilities move Kylian Mbappe become the central forward and Vinicius Jr keep playing on his real position as left winger. Its make more completed with Real Madrid attacking line on right side will fill by Rodyro and has Mbappe on central forward position then Vinicius Jr will fill the left winger position.
In Real Madrid, Vinicius Jr has long term contract and I don't think Madrid want to sell or put him in the bench after arriving Kylian Mbappe next season.
Mbappe needs Madrid but on the other hand, Madrid doesn't need Mbappe, hopefully the composition that Madrid currently has continues to work well. Although it cannot be denied, the fact that Mbappe is getting closer to Madrid and has to sacrifice the position already occupied by Vini will sound a little forced. Mbappe being installed in the middle is not suitable, but if Ancelotti wants it, I think Mbappe has to accept it. Or swap places with Vini, it all depends on both parties and I'm sure this will be a difficult choice. For example, other options such as sharing time are clearly not Mbappe's goal because he came to Madrid wanting to get regular playing time.
Actually the truth is opposite with that you saying, Mbappe doesn't need Madrid while Madrid needs Mbappe. Madrid is still seeking a good center forward, that's why they sign Joselu. Vinicius and Rodrygo will back to their respective positions, just like when Benzema was playing for Madrid.
Vinicius itself still don't have a good finishing skill, Ancelotti is forced to let him play in center forward position.