A modern midfield is typically made in two different ways:
Option 1 is the way Barcelona and Portugal play.
A pivot who takes the ball of the centre backs, sniffs out danger and feeds the ball forwards to the advanced midfielders. Best in the world at this is Busquets. Barry did this for us.
Then two midfielders who operate as all rounders - think Xavi/Modric/Iniesta/Moutinho/KDB/Silva
They must be able to keep possession, both to get the ball into their front players but also to control the game.
Other option is to have a double pivot, with a sitter, a box to box and an attacking midfielder. Think France with Kante and Matuidi giving Pogba more freedom, or even us with Barry, McCarthy and Barkley.
At the moment we don't have anything but the box to box - Davies, McCarthy, Gana, Scneiderlin do that adequately but only Gomes can do the all rounder role.
In Everton terms we need our Barry, Arteta and Barkley to get that combination of passing and the ability to break lines with forward passes and dribbles.