https://www.whoscored.com/Players/115916/Show/Fabinho
I know stats aren't everything, but Fabinho is DM in the mould of Carrick - calmness, positioning and passing in the middle of the pitch. Also has the height for set-pieces and takes great penalties. Getting Fabino and Morata means we can play a 433, with Herrera and Pogba pushing up more to support the attack with the knowledge that they have Fabinho behind them for cover. Essentially, an upgrade of present-day Carrick.
Only problem in a 433 is that the front trio have to start scoring. We were too reliant on Zlatan last season, and our wingers (more like inside forwards) did not chip in enough goals. However, with a 433 and assuming Darmian is at LB, our formation when attacking can shift to become a 3-1-4-2, with Perisic providing width from the left and Pogba pushing up from left midfield in the space that the opposing RB vacates. Similarly, we have Valencia pushing up on the right, linking with Herrera, while whoever was starting nominally on the right flank will be alongside or around Morata. Darmian will then tuck in from the left to make a back 3, with Fabinho just ahead of them.