I know this will get some flak, but I don't think Dihno plays "about as optimally in our system as anyone can expect." I think he is superior in the air but quite weak under pressure and his passing can be quite wayward at times.
So you f a team chooses to press us hard and often, Dihno is one of the weak points in that press. Thankfully though, the addition of Laporte and Zinchencko has made pressing us that much harder.
Now if we can find a young player with most of Dihno's defensive skills, but more cultured under pressure, such a player will potentially surpass Dihno at the DM position.