getting Jittery movement on camera when player rotating and moving in same time

Hello all, I'm trying to create a smooth camera follow script but I don't know why I'm getting "jittery" movement....even I'm using "FixedUpdate" in PlayerMovement.cs script for player movement sach as rotation and movement, and the "LateUpdate" in camera follow script and also I set player "RigidBody" to "Interpolate".. Any Help appreciated thank you.

these are my scripts:

Blockquote

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class CameraFollow : MonoBehaviour
 {
     private Transform playerTransform = null;
 
     [Range(1, 10)]
     [SerializeField] private float smoothSpeed = 5f;
     [SerializeField] private Vector3 offset;
     [SerializeField] private Space offsetPositionSpace = Space.Self;
     [SerializeField] private bool lookAt = true;
 
 
     private void Start()
     {
         playerTransform = GameObject.FindGameObjectWithTag("Player").transform;
     }
 
     void LateUpdate()
     {
         if (offsetPositionSpace == Space.Self)
         {
             Vector3 desiredPos = playerTransform.TransformPoint(offset);
 
             Vector3 smoothPos = Vector3.Lerp(
                 transform.position,
                 desiredPos,
                 smoothSpeed * Time.deltaTime);
 
             transform.position = smoothPos;
         }
 
          if (lookAt)
         {
             transform.LookAt(playerTransform);
         }
         else
         {
             transform.rotation = playerTransform.rotation;
         }
     }
 }

Blockquote

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlayerMovement : MonoBehaviour
 {
     Rigidbody rb;
     [SerializeField] private float speed = 50f;
     [SerializeField] private float mouseSensitivity = 100f;
     [SerializeField] private Transform playerBody;
 
     private void Start()
     {
         rb = GetComponent<Rigidbody>();
     }
 
 
     private void FixedUpdate()
     {
         ProcessInput();
         ProcessRotation();
     }
 
     void ProcessInput()
     {
         if (Input.GetAxis("Horizontal") > 0)
         {
             rb.AddRelativeForce(Vector3.right * speed * Time.fixedDeltaTime, ForceMode.VelocityChange);
         }
         else if (Input.GetAxis("Horizontal") < 0)
         {
             rb.AddRelativeForce(Vector3.left * speed * Time.fixedDeltaTime, ForceMode.VelocityChange);
         }
 
         else if (Input.GetAxis("Vertical") > 0)
         {
             rb.AddRelativeForce(Vector3.forward * speed * Time.fixedDeltaTime, 
             ForceMode.VelocityChange);
         }
 
         else if (Input.GetAxis("Vertical") < 0)
         {
             rb.AddRelativeForce(Vector3.back * speed * Time.fixedDeltaTime, ForceMode.VelocityChange);
         }
     }
     void ProcessRotation()
     {
         float mouseX = Input.GetAxis("Mouse X") * mouseSensitivity * Time.fixedDeltaTime;
 
         playerBody.Rotate(Vector3.up * mouseX);
     }
 }