This is why PSG being managed by Zidane is not just a want, but also a need. If they can somehow get him, then they are going to be getting everything they will ever need. On the other hand, I agree that it's not going to happen and I believe Nagelsmann would be the only one left for them to hire but that's not going to be enough if you ask me. They aim at being one of the best clubs in the world, and in order to have that you need to have one of the best managers in the world.
There is no way Zidane is going to manage PSG knowing that he is probably not going to find huge success. If he is actually going to take a managerial job, I believe it is going to be in Real Madrid again or probably any other team in English Premier League. He's not going to go to some club which basically does not have any competition in the league itself.
Nagelsmann can be a good choice for PSG. But again at this moment, managing PSG is not easy because the expectation is to win the Champions League title, which is obviously the hardest trophy in the club competition to win. But it can also be a fan experience for a new coach because he is going to have access to a huge amount of money. But he will have to show some success.