I think your problem here is that while your wing-backs are both pushing up to join the attack, the centre-backs are effectively operating a staggered back-three with the Stopper pushing ahead of the Defender, with Cover-man behind him - making it easy enough for the opposition to play in-between them and work the ball into the unguarded wide areas for crosses. When I play with three centre-backs, I have DC_Defend, DC_Ball-Playing Defender and DC_Defend. They tend to spread out across the width of the pitch the higher upfield they go, and close up together when retreating towards our goal.
On corners, set it up manually. You want your tallest, best heading DC to Mark Tallest Player; the other two should Man Mark; put the wing-backs on the posts; DM to Mark Small Player; CM to Edge of Area; if one of your forwards is good in the air, tell him to Go Back and have the other forward and your AM Stay Forward to orchestrate counter attacks. If your AM can run with the ball at speed, so much the better.
On a separate note, have you tried a Regista in the DM role? If you have a player suitable for the role then I'd encourage you to give it a go. They knock the ball around like Michael Carrick at his best and help you to retain possession all over the park. You might need to change your CM to a Ball-Winning Midfielder_Support though, to add some steel into your midfield. And, make sure your Complete Forward is playing on whichever side of the attack corresponds to his strongest foot; it makes a difference to his ability to hit the target when he makes runs into the channels.
View attachment 338780
The screenshot shows a similar formation that I have created - haven't been using it long enough to judge how successful it is, but I have had some joy with it. With the Advanced Playmaker starting from a deeper position, he can run with the ball and build up some momentum that often means defenders moving out of position or fouling him. And the whole team moves up behind him, so the formation is not nearly as defensive as it might appear.
