I totally agree with you. Letting go of Pep would be a huge mistake. He is the reason City has been so dominant, and even though this season has been rough, replacing him isn’t the solution. The squad needs reinforcements, not a new manager. A few key additions in weak areas could help City bounce back without disrupting the stability that Guardiola brings.
Why do you think a change of manager will be a mistake for the City? Was Guardiola there in the first place? No! He has made a lot of contributions since joining the club but it took time, his contribution just came at a point but he spent most of his years toping the table but don't win when Liverpool, Manchester United and Chelsea were taking all the glory, if he is change today, the club will stand. It's possible they might see short term draw back but will do better with another person.
What City majorly need is not coach replacement, the problem isn't about Guardiola alone, it's about the team connectivity, they have loss that touch already which need fixing. Some of them need to be relieved of their responsibilities, they are just here but their spirit is not given what they did in the last 3 years, they are not playing with dedication that's more reason why they should be replace with new players that has something better to offer the team.