But that would be the worst timing ever if they now sign Zidane when Mbappe is about to leave the club. By the way I doubt that if Mbappe leaves the club, Zidane would not want to become the coach there. They should have tried like never before when there was still Neymar, Messi and Mbappe. But I think at the time Zidane was still a coach (or again) at Real Madrid? I am not sure about the timeline back then, but I think that was the situation. Now when Mbappe leaves PSG is not the same team anymore.
I think this is not a bad thing, we all know what PSG's standards are if the coach is unable to provide trophies other than league 1. PSG will replace him with a new coach, PSG has the authority to continue changing coaches so that they can achieve success not only in league 1 but also in the Champions League, but it depends on Luis Enrique whether he is able to bring PSG to a better level in the Champions League or at least can reach the final round even though he has to be runner up then he will be retained but if not, maybe he will suffer the same fate as the coach previous trainer. Moreover, PSG does not have strong performance like Manchester City and Real Madrid to compete in this big competition, so it is not wrong if they are in doubt about winning the Champions League title.
Zidane is a great coach even though PSG was relatively late in recruiting this good coach because Mbappe was about to leave PSG, but PSG didn't appoint Zidane because Zidane decided to take a break after becoming Real Madrid coach so PSG couldn't offer him, but now it looks like Zidane has wants to return to the training chair and wants to take on a coaching role again but we also don't know which club he will manage. PSG has sufficient resources. If Zidane trains PSG then Zidane can buy the players he needs and he can create his strategy according to the capacity of his players.