He covered Haaland for a chunk, but Haaland wasn't injured for 8 months!
He got a lot of starts. No one knows 100% why he left, it's just speculation
It wasn't just Erling, Kevin or anyone, or being used in a wing, etc...the main thing that I was saying it's that putting the ball fast for him at least one of two times of the many times when he ran into space wasn't going to happen in City at that time and less when he played depeer, or wider.
This has more to do more with him not feeling entirely "there" than him in the pitch with or without Erling.
Of course at that time the set up of the team with Erling there had more inclination to not create situations like the one I was reffering being more suitable for him, yet for instance he got along quite great with Erling and at times with Foden. It was with Bernardo, Palmer, Jack, Doku and even Kev where they rarely used him as final destination, combine more with an assertive play , etc.
In Aleti he can drop, ran into space, combine, etc basicly see more of the ball in better situations to exploit his pace and intelligence to find pockets of space, even if Aleti is less offensive and he has to capitalize better what ends being a clear situation.
Indeed it's mostly speculation, yet the stuff I'm saying was there to be seen. In fact happened even to Erling quite a lot too when he tried to be more direct and noone was putting the ball ahead of him.
Lately Pep has been more keen to do it, to let players risk it a bit more in certain matches but it's hard for him to let that style develope no matter the characteristics of his players and he certainly has do it
quite well with this approach becoming one of the very best coaches ever.