What you wrote makes no sense, even when trying to defend Pogba you expose the issue. First when you have Pogba, McTominay and Fred on the field your midfield is made of all of them, it's not a midfield of McFred. And the issues with that combination isn't the individual roles that these players have or can operate in but how they collectively fit with each others. That midfield has never been complimentary, collectively they don't give us all the elements that a functioning midfield require.
In isolation Pogba has been used in a role that suits him but that role doesn't suit with the players next to him and unfortunately the players next to him don't even fit with each others. You could make the same point with Bruno, we are using him in a role that suits him but his role doesn't suit our needs nor does it fit with his teammates.