I can't figure out smoothing a rotational move. Tried lerp, slerp, all the stuff.

If I'm inputting axis horizontal I call this:

 Quaternion newEulerAngle = Quaternion.Euler(transform.rotation.eulerAngles + new Vector3(0f, 0f, (-turnInput * turnAngleStrength * Time.deltaTime * 5f)));

I just want it to happen slowly. Right now it snaps to the stick. I want to turn the stick all the way and have it slowly catch up. Smooth it out. Dampen. I've been trying for days...

Thanks for any insight.