Well, I will commend Pep and city for signing a new goal keeper but Manchester city problem is not the goalkeeper but the defence. It seems Guardiola is already out of ideas managing this team after all he's done for them in the recent years. I don't understand why he let go of Akanji when their defense is in shambles and then assumed a new goal keeper would solve that problem. Ederson was never a bad goalie but the weakness in the defense made him look like average goalkeeper and the same thing will happen with Donuramma if nothing is done about the poor performance in the defence.
The difficulty for City's defense is their style of play, they are an attacking team and spend a lot of time near the opponent's goal, and this creates conditions for counter-attacks, in such conditions the team will concede. I think it all started when Walker decided to leave the team, this was a significant step for City's defense. I think Guardiola does not understand what exactly City's problem is and he is trying to fix it by buying new players, but he has no other choice, and if the management approves new transfers, he will buy new players.