Mbappe 100% wants to stay for another year and leave, that's his stance and we understand it, he has said it literally himself, there is no doubt about that part. The stand points of both sides are decided already, we just don't know what can be done about it.
PSG also wants him to either extend or they will sell him, no intention of sending him away for free, so either he extends or he will be sold, that's also understood. But on this case, what could PSG do if he doesn't leave? I mean if he refuses to leave, then there isn't much they can do about him, just bench him all year long? I do not think so, fans would be mad, the whole world would question that. If he wants to stay one more year, PSG will have to stuck it up and just let him play for another year and then leave.
The news of Mbappe staying with PSG is undoubtedly the most exciting one. Looks like he is playing a clever game, aware of his desire to leave but also mindful of not letting down his loyal French fans and the PSG community by forcing an early departure. Mbappe is well aware that his contract will expire after the next season, and his club have to let him go as a free agent. Consequently, the pressure is on PSG to sell him this season and making profits. The summer transfer market closing in September, still possibilities to happen anything.