Certainly, firing Guardiola before the termination of his contract with Manchester City at the end of this season is not a good decision for the Manchester City management. He has uplifted the team to very high ends previously unattained by City. The last four losses are a letdown, but considering how much he already gave to Manchester City, Guardiola has already brought home so much silverware, including the one everyone wanted, the Champions League. He transformed the style of play for City into one very much based on cohesion and dominance in multiple competitions.
Pep Guardiola is a legendary coach with his successful career from Barcelona, Bayern Munich to Manchester City. It's hard to find another coach who can replace Guardiola successfully and bring titles and domination like what he has done with Manchester City last 6 years.
This season looks to be not too good for Manchester City but the season is long so that Manchester City can come back. They have some big disadvantages for making a come back, most considerably their player injuries and lack of good replacements. It's hard to imagine a rich club like Manchester City now don't have enough players for playing and rotating.
I don't know why they let Julian Alvarez left their club in the summer because he is very useful for them as a substitution and especially if Haaland is injured, Alvarez is a perfect replacement. Maybe the player no longer want to stay in Manchester City and play with a substitution role, or maybe Manchester City didn't try their best to keep Julian.