I get what you are trying to say. And I agree with part of it.
But you are missing one aspect in that post.
Question is not that much where manager X or Y is managing. Question is - what is the position of the club he is managing in context of it's competitors.
Celtic is THE powerhouse in Scotland. In terms of it's capacity it is two heads above everyone else.
And there are managers that suit into the the dominant clubs and there are managers that can do well in clubs with different standings. Who can adjust and change around more based on the limitations when you do not have the exact right option that you would need.
Ange has shown in countless of occasions how he is unable to make alterations. He just seems to be the manager who can win you the league in style. If you provide him with (roughly speaking) best player in every single position. If not it's gonna be mostly horrific spectacle. As it has been for us vast majority of Ange time here. He just does not fit into our position. And based on that spell here, no dominant club in their league (your ManCity, Liverpool, Real, Barcelona, Bayern, PSG) will never poke him with a pole that is even 10 miles long.