It is the poor quality of signings that are causing City's deterioration.
Their lineup today is nowhere near good enough for the budget and reputation they have, they could sign much better players. Doku, Marmoush, Nico Gonzalez, Bobb, Trafford, Lewis, none of those are even close to being considered amongst the best in their position.
The problem is that they don't have a centreback at leftback, a centreback at right back, two centrebacks at pivot and two centrebacks on the wings.
Pep gets those signings and he can turn this around.