If the ctrl is attached to the head joint and you use that ctrl to rotate the head joint, it’ll create a kind of rotation loop, where you’re rotating using a control that is rotating the joint where the ctrl is attach to, inheriting the rotation from the joint.
Usually when you rig, you want to have ctrls indipendent from the hierarchy.
Check the many CtrlRigs in Lyra or any other UE5 sample project, you’ll see that the ctrls are outside the skeletal hierarchy.