I don't know if Neymar can find himself a team in Europe at the moment. His contract expires in 2025 so interested teams have to pay a transfer fee as well. The reason why I stated it is that his market value is still 70 million euros. Of course PSG wouldn't demand that much for a 31-year-old player. But I wouldn't expect them to demand less than 40-50 million euros anyway. Moreover as far as I know his current salary is 36 million euros per year which is an enormous sum.
I don't know if there would still be a team to be okay for meeting all these demands. Hence I expect him to stay here for a long time unless he gets an offer from outside Europe. As for Mbappe I don't expect him to leave this summer either. But for next season it is doubtful. If PSG fail in winning the CL title again then maybe we might see him at Real Madrid right after that.
Mbappe came close to signing a deal with Real Madrid last season but in the end PSG agreed to all his terms and kept him at the club with a huge salary cap. But Mbappe has realized this season that if he doesn't leave PSG, he will never win the UCL trophy and never win the Ballon d'Or. A footballer's dream is to win the Ballon d'Or. I hope this time Mbappe will focus on his career instead of being greedy for money.