How to use Transform.TransformDirection of another transform to affect a separate Transforms local rotation?

I'm trying to create a third person Shooter on the mobile platforms.

My current hierarchy is as follows:

Transform - Player

Transform - Weapon

Weapon Transform Child - Target

The player uses animator to move and the weapon transform is used to rotate the weapon via Inverse kinematics. The weapon points at the target.

The problem arises with the player changing direction, i use:

targetPoint = new Vector3(sphereTarget.transform.position.x, transform.position.y, sphereTarget.transform.position.z) - transform.position; targetRotation = Quaternion.LookRotation(targetPoint, Vector3.up); transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, Time.deltaTime * 2.0f);

This has the player's transform(with the animator and collider) facing the direction of the target. I want the rotation to be relative to the players transform at all times, but this does not change, the rotation at the moment is in world space and not local space.

If i child the weapon transform to the player, i can use its local space correctly and can get the weapon to rotate with the correct direction, but doing this causes the player to spin out of control as it tries to follow the target within its own local space.

So i've come across Transform.TransformDirection and i need help in making sense of how i could use it to affect the rotation without parenting transforms.

Code i use to rotate weapon:

 angle2 = Mathf.Atan2(joystickxy.x, joystickxy.y) * Mathf.Rad2Deg;
 
 weaponTransform.localRotation = Quaternion.Euler(0, angle2, 0);

Any help is appreciated, thanks.