He deserves to be judged by him missing chances, and he missed a few this last game, not all of them clear cut ones BTW...
Yet what few times it's said, is that Pep's teams, specially City, play to the strength of the Bald One ideas and the strategy he wants to apply a certain match (it's not a pun, he is an extraordinary manager, it's just what it is).
This sometimes will make any player at his disposal flourish a certain day when things go well because of being in form and the idea and tactical disposal of that day reinforces his attributes. It can get harder if the role assigned to any of his players a certain match doesn't suit the player in question best attributes, yet Pep mostly wins because almost every approach he tries enhances the strategy that can provide a win, so the team or other player becomes the ace of spades under such idea.
I'll put some little examples that happened in the last match. On a flank there was Alvarez and Doku, that it's an odd combination, the first one has some dribble in him, but is more of a passer, one/two combination type of player and more central forward oriented. The ammount of times Alvarez didn't face his marker, or Doku didn't release the ball fast in a one/two and also hold the ball unnecesarily and other nuances, repeated the whole game.
On the other hand Phil wasn't on his best form, didn't have Hallaand as close, or Julian to combine and tried too much to dribble while being mostly in a flank where he doesn't feel that great.
Hallaand had his chances, but the big lad likes to combine coming from the middle, to run to space, to play with Foden/KDB/Alvarez, to create and go into spaces. Him playing surrounded by tones of rivals, or an in the box striker, doesn't suit his nowadays tendency of playing.
Of course he must develope it in the future, he has the physique and with age he will have to turn into a big box player.
So at the end of the day if Erling or any other scored his chances thsi last game, City could have won, but like so many times with City, it doesn't mean that the idea for that particular match suits like a glove the characterictics of a particular player. Pep soemtimescan somtimes make an 11 with almost all of them doing sthg. not that common for them.
That is why he clashes too much many times with Superstars not named Messi (of course he did have fights La Pulga, but like Mou, Cholo, Jurgen, Ancellotti, or whomever he won't be as daft as thinmking you need to coach a lot a Pele, Romario, Maradona, Alfredo, Messi, R9 or such, you just have to be smart and try to create the best enviroment and avoid clashing while at the same being firm and generate respect from them).