How to stop propagation of bone rotation.

I’m searching for a way to rotate only the middle of bone hierarchy.
The problem is that the rotation of the parent bone always affects the hierarchy below it and there is no option to stop it.
Transform Bone and Copy Bone transform only the initial state and can’t stop rotation.
This is a very easy problem to solve for Blender. But in UE even if I try a very complicated method it fails.
I’ve been working on this problem all day, but I can’t find a working solution. How can I solve it?