I agree with you, Guardiola is a genius coach and that's it.
But after all Pep Guardiola will not be able to guarantee anything next season even though he won the treble winner this season. A lot of people didn't expect him to defend the Champions League title, but they weren't Manchester City fans.
There is a possibility that Pep Guardiola will also be successful with Manchester City next season because he still has many quality players. De Bruyne and several other senior players will not be as strong this season, but they can still contribute well.
Pep Guardiola is smart or genius head coach for Manchester City and supported much money for making his job easy signing many star player, I don't think what happen if Pep Guardiola as mediocre head coach and smart is he bring success teams without support much money. For next season, seems Manchester City are favorite team for winning many trophies and Champion League because Pep Guardiola has many qualities between main and substitute player. Last rumor Pep Guardiola will signing several potential player and seems easy for him defend treble winner for next season.
But Manchester City have extend some player from İlkay Gündoğan and Bernando Silva because they have a lot of contribution for making The Citizen success with treble winner.