I'm not sure that Calabria is better than Conti. Calabria is just stupid, getting himself sent off for lazy defending, and on the ball he always picks the wrong pass. Conti although an idiot in his own special way, I feel can add something more as a right wing back. He is better in motion than Calabria and in that position you dont need to worry about him defending inside the box.
Hakan is better than Paqueta at the moment, the latter only gives 30 mins of effectiveness, he seems like a better option coming off the bench at the moment, but perhaps pairing him with Hakan behind a CF would be the best for him.
Leao is better than Piatek but Piatek is more clinical, with the formation I mentioned, Piatek should start because it focuses a lot on the contribution of the wing backs and their crosses, it needs a player who finishes with one touch. I would like to see Leao and Piatek the same time eventually, especially when the game opens up and you get chances.
We need 3 CBs at the moment, we are too exposed at the back. Our full backs do not cover the space so good and Musacchio does not win duels. Our midfield is not creative anyway so you might as well stack it with ball winners and shoot it out to the wings or to the attacking minds. In the formation I mentioned you have the wing backs and two attacking midfielders as quick counter attacking options.