I think the matter of Kylian Mbappe's future isn't supposed to be the a case of discussion now that the transfer window is over. Kylian Mbappe is a Paris Saint Germaine player and will continue to be their player till the end of the summer. Luis Enrique has been given all the necessary backings he needs to succeed in his first season as a PSG manager.
Though Mbappe wants to leave the French capital to continue his footballing career, but it's been reported in the media that he's going to sign a one year contract extension with the club so he can be sold for reasonable amount of money when he'll be leaving next summer.
I have read the rumors you said in this post, this idea even emerged after Mbappe rejoined the PSG squad. but unfortunately, there is no concrete news that reports what really happened. So, it would be very natural if there was a lot of wild speculation reported by many sports media. However, currently Mbappe is still playing under Luis Enrique. in fact, he has contributed 4 goals from his 3 matches with Paris Saint-Germain. His presence again means a lot to Luis Enrique and the PSG squad. it's just that if we talk about Mbappe's contract, this season is his last season with Les Parisiens. either he will leave for free, or PSG have a new deal with him. In essence, Mabppe will leave next summer. Thus, Luis Enrique must prepare his team's squad to find a potential replacement. I think, with the finances they have, PSG can bring in other talented players. so, in the end PSG must be ready for the departure of its star. the point is at this time, PSG must show their best game. both in the Ligue 1 League, and in the Champions League. Enrique has a duty, to bring their team as far as they go, especially in the Champions League.