When Klopp left Liverpool the same thing was said of Liverpool but today they are not just dominating the premier league but also the UCL courtesy of Arne Slot. Who knows Gaurdiolla's era in Manchester City might be over and thus needs to start a new career else where. If City deemed it fit to let him go then their wish should prevail.
Sometimes we don't need to stick to a system because of it's past, it could be the glory of that past no longer applies to the present. If City has found a perfect replacement for Pep then let them.do their experimentation and see how well it ends who knows they might bring back the competitiveness in City yet again.
I do tell people that with good players and average manager, a team can win any competition but with excellent manager and average or bad players, a team will only suffer in the any league they found their self. Liverpool has Klopp as one the great managers and Liverpool has combined quality players that's why when Klopp left and was replace by Arne Slot as average manager, the team is doing well and topping every league competition they find their selves.
I can't say the same thing for Arsenal because they don't have one of the best players with average manager. Manchester City used to have best players and best manager but the two were compromise. The manager was having marital instability and loss of wealth due to divorce and the diversity of players lead to the fall of the build of the team and that's why they are having bad time processing every games they have, they are now programmed in their head like they are built for failures.