We rely heavily on Amrabat the next month

doesn’t matter who our DM is. Under Ten Hag’s system, they will always drown. It doesn’t matter whether it is Amrabat, Cas, Eriksen, McT or prime Makalele.

If you’re building up in 3-1-6 shape, the 1 (DM) will always recieve the ball in trouble. The passing lanes towards him are shadow pressed so he will receive the ball under pressure from several angles. His passing lanes are also cut off because the other midfielders are in the half-space.

Did not appear to be a problem for Mainoo, did it?
 
Did not appear to be a problem for Mainoo, did it?
But it was. Look how many times they run through our midfield. Mainoo was just better individually/faster and more energetic than Casemiro/Amrabat will ever be. I am not that sure if he's that good defensively anyway, at least it doesn't seem like his best side compared to how good he is on the ball/ when we're in possession.

But back to original point, there is no player that is capable of playing DM position in this Manchester United setup.