So far as Manchester City have Pep Guardiola they still have the chance to win the Champions League next season, Pep Guardiola is the main engine box for the Victory of Manchester City in Champions League this season. Pep Guardiola is a coach that understands how to win trophies and how to use players to get what he wants. I know Manchester City does not have much experience when it comes to Champions League but they have a coach who is capable of making a squad to be tough to win competition.
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.
Next season Manchester City will still remain one of the best team in the Champions League, but it won't be very easy for them because teams like Bayern Munich and Real Madrid will improve and to do better than what they did in the concluded Champions League. No doubt that Manchester City is a strong team, but it was so possible for them to win the league because of the poor performance of Real Madrid and Bayern Munich.
I'm still backing Manchester City to win the Champions League title next season, so I have no doubts with them. But of course, some additions player next season are expected as Mahrez and Gundogan are unlikely to stay around.