There might be plenty of reasons why they lost, and no positivity showed by Pep's squad.
He has been at Manchester City for many years. And he has achieved a lot in those years. His reputation will not be damaged because he had one season of bad results. But he should already start thinking about next season. Either he should resign from his position or he should start planning the squad now. The current squad consists of footballers who are saturated with success. He can turn the team back to its old days by transferring young players hungry for success with his brilliant tactics.
Football quickly forget loyalty and that's very bad thing to over look. Guardiola didn't just wake up one day to start working as coach for Manchester City, he has won Champions League in Barcelona and other prominent trophies their before he came to Manchester City. When he got here, many people said it's because of Messi performances he was able to achieve all that but he proves them wrong and has won many trophies here, so I don't know why this so where we draw the line of failed manager.
The problem of Manchester City performance is a combination of many factors, the players, the coach and the squad. We know Guardiola is dealing with marital problem, I don't know much about the state of the divorce but he is definitely dealing with a lot right now, no one will enjoy losing half of their wealth with a woman that might have probably not stood by you when you were there working your ass up. The players also need to be deleted and replace, some of them are just here doing nothing.