Even if Pep Guardiola lose more than half of the matches he will play this season, I don't think Manchester city will ever think of firing him because his achievements so far is bigger than just one season of bad results. Pep Guardiola is the man that made Manchester city what they are today. He transformed the club to what we are seeing today, so there is no amount of bad results that he will have this season that will make his club sack him. Just like every aspect of human lives, things ain't always good all the time, so it is just one of those things in life. We have seen Pep lose matches in the past and he always comes back stronger. Pep Guardiola is definitely going to respond with winning streaks. There are managers that are beyond sacking and Guardiola has earn that badge of a manager that's beyond sacking in my opinion.
There are two different reasons for that. First of all, it's true that he will not be fired because he won so much, and not like they are 14th or something, they are still doing fine at the moment, in theory they can literally do the treble this season, and there is nothing mathematically impossible there. They are still second in the league, only five points behind and they could still win the league. They are going to play FA games which they could still win, and at UCL they are still going to go up the group stages we know that.
So basically what I am saying is that, they could finish the season with zero cups, but they still have a chance at all three, so no reason to fire someone who has seen so much success. Plus, the second reason is, he is leaving at the end of the season anyways.