Barcelona doesn’t deserve to be on the list, in my opinion, because they are not in good shape.
People who think Barcelona is strong definitely a Barcelona fans that can't judge something base on objectivity, similar to Manchester United fans. 
Kevin De Bruyne is a very important player for the team and Manchester City are lucky to have him back in training. We can say that it was a generally bad season for Barcelona. Even if we see Guardiola come to Barcelona as a coach, I don't think anything will change because Barcelona is problematic in other aspects. Without improving the financial situation, they do not have much chance for long-term victories.
Barcelona is a failed team after Messi's left for Inter Miami, the socios aka Barcelona's supporters need to sell their team to the rich person. So they will have money to rebuild the team by signing popular players.If for example Pep Guardiola returns to Barcelona, I personally believe Pep Guardiola will be able to restore Barcelona's performance. But yes, if for example Pep Guardiola still fails to restore Barcelona, then this will be proof that Pep Guardiola can only succeed at a club that has good finances . Therefore, it seems like it would be interesting if, for example, Pep Guardiola dared to return to Barcelona because yes, if Pep Guardiola managed to restore Barcelona with financial chaos like this, then Pep Guardiola would be the greatest coach of course . Because yes, basically Barcelona still has a squad that can be said to be good and therefore, if for example Pep Guardiola returns to Barcelona, I personally still believe Pep Guardiola will still be successful.