Guardiola may not be planning to leave Manchester City at the moment as there is no reason for him to leave the club at the moment.
Nothing last forever in football and all successful cycle has its start and ending so Pep Guardiola knows when to leave Manchester City. He will continue to manage Manchester City and consider his player performance in next two seasons to decide he will sign a new contract with Manchester City or leave. If new players can replace current players and increase the club strength, Pep will consider to stay a few more seasons. In contrast, if things are not well, Pep will know that is right time for him to leave at successful time in the club.
PSG will improve if Guardiwala goes to PSG but recently former Barcelona manager Luis Enrique took over as PSG manager. Luis Enrique is an experienced and tactical enough manager that PSG will improve under him. Luis Enrique has already joined the PSG training camp. There is no chance of Guardiwala going to PSG at the moment as Luis Enrique has taken over as PSG manager.
A good manager does not take responsibility for any team that he can improve with. Good managers agree to work with that team.
PSG needs more than a coach like Pep Guardiola but they need a completely change in their development strategy, from player transfer to player salary and power they are ready giving to their players.
Paying players too high salary will make them lazy, arrogant with their team mates and break many good relationships internally among players and coach. That all together will impact their club performance in Champions League. So PSG have a lot of things to change if they want to sign with Pep in future.