Kylian has stayed with the team but his mind is still elsewhere. I don't know if he can fully contribute to the team. As it is known, PSG put him on the sales list, but no team can afford this high cost right now. Even if he does, there is a priority team for Mbappe and he is taking every opportunity to go to them. It may be playing with PSG this year, but it may outperform last year.
Although Mbappe is currently very young but his professionalism at work I think he is a pretty good player so when he decided to extend his contract at PSG (although there is a record of being sold next season) he must have thought carefully and will be serious (professional) with his decision.
As for when PSG plays and loses, it does not mean that Mbappe is not doing something good and unprofessional but he himself is not able to bear all the players so that when he plays well it is very useless if the other players do not play well.
Unless his form drops this season it might be an indication that he's not serious but looking at his current condition I think he always does his best even if the results don't match expectations.