I also don't understand the greed by Manchester City... They've already signed James Trafford for 30m euros. They have a backup goalkeeper who is Ortega also.
Then why are they going for Donnarumma too?

I don't think Trafford would be happy about giving his starting eleven place to him.
I'd rather see Manchester United going for the Italian goalkeeper as they need the most now.
The plan is that City was willing to get red Ederson and Ortega. They will replace them all with Trafford and Donnarumma.
As for Trafford, i know it sounds harsh for him to have Donnarumma come as a new goalie, but this is a part of process. He has to compete with Donnarumma for the first spot. I'm sure that competition will push him to break his limit. He's a good goalie, but bring a competition for him is a must.