Since zidane was not even giving single sentences regarding his future club and i think that's actually useless to talk about him. He has been rejecting any clubs that linked to him.
He is smart and disciplined. He knows what he want, a France national team's coach position. He does not need money from rich clubs and he can wait a few more years to take over his national team coach position. I guess Zidane knows that France currently have a very good squad with many talented players and many of them are young and can grow up more. If he takes over that position, he will have good chance to win big titles with France like World Cup and Euro and even can repeat success of Spain, winning three big titles during 6 years (1 World Cup, 2 Euros).
PSG is now having more important mission to rebuild the club as so many players have been leaving the club including one of most important player. PSG will be playing without mbappe next year. That means if PSG will be also losing another potential talent again from the club.
We don't know about future of Mbappe, lot of things can happen in future, this summer or next summer.
As you can see that the future of neymar is still remain uncertain.
He wants back to the barcelona while barcelona is now focusing to rebuild the club with so many young talented players. I think that the possible thing if neymar will be staying even longer in PSG.
He will not go to the another club in summer. Neymar's contract is still remain a bit long at this moment. I think that neymar gonna be staying in PSG.
If Barcelona did not bring Messi back to their club, they will not bring Neymar back to Nou Camp. Neymar is younger than Messi but he will require high salary that will not be paid by Barcelona with their not too good finance recent years. He is sensitive with injuries and Barcelona will not pay expensive cost for such players.
Neymar might leave PSG but his destination will not be Barcelona.