How to get CDMs to fall back behind ball when defending?

As above... I play 4-3-3 ( 3 )... the one with 2 CDMs. How do I get my CDMs to fall back behind the ball (alongside my defence) when my opponent is attacking?

I've seen some of my human opponents do this. When I attack, their CMs/CDMs basically function like additional defenders.

But for me, my CDMs will just "hang around" slightly beside and in front of the ball. The perplexing thing is... my CM is usually the furthest back. I can manually pull (one of them) back by actively controlling, but once I switch, he moves up in front of the ball again. And I can't keep doing that because I need to control other players to defend the opposing player with the ball.

It is not that they can't get back in time because of fast counters. Even when the opposing player is slowly passing the ball up, they still just "hang around" and don't even bother to jog back behind the ball. I always use CDMs with H defensive workrate and decent defence attribute (at least high 70s).

I've tried both with more mobile (but still defensively decent) CDMs (like Tchouameni and Tonali) as well as less mobile but more defensive-minded ones (like Rodri and Casemiro) but the results are the same. In fact, worse for Rodri and Casemiro because it is more difficult to pull them back in time (because they are slower).

I've tried tweaking custom tactics:

- Setting defence to "drop back"

- Setting defensive depth to 1

- Setting the 2 CDMs to stay behind when attacking

but none works. In fact, any tweaking away from the default seems to make things worse. At least with default, they don't "hang around" too far ahead of the ball.

Any ideas, please?