Playing against Exeter, Salford and PL teams adjusting for the cup will do that. I dont think Trafford looked like a nailed on starter in any Premier League game this year.
If Maresca is that dogmatic, he's doomed to fail. Donnarumma doesn't need to be heavily involved in the buildup. All he really needs to do is recycle the ball quicker. That's more of a tendency issue than ability. He held on to the ball longer than needed a few times.
Your keeper isn't there to be your playmaker. Ederson was a luxury in possession that you can't replicate. If Maresca is any good as a coach, he's simply making sure Donnarumma plays the ball quicker to escape the press.
Even with Ederson, they'd drop Rodri to CB and spread the other 2 CBs wide to overlap any high pressing if teams actually press rather than the ones who just come to the Etihad and play 8 at the back.