Smooth Camera Rotation After 2 Seconds

Hey, I want to rotate my Camera slowly 2 seconds after the script starts but my camera always rotates instantly to the new angles. Can anyone please help me with this? I tried a lot but nothing seems to work :(

Here's my code:

  private void Update()
         {
             if (cam.transform.rotation.z != 0 && cam.transform.rotation.y != 45 && camMovement == null)
             {
                 camMovement = StartCoroutine(MoveCamera());
             }
         }
     
         private IEnumerator MoveCamera()
         {
             yield return new WaitForSeconds(2);
             cam.transform.rotation = Quaternion.Slerp(cam.transform.rotation, Quaternion.Euler(0, 45, 0), 1f * Time.deltaTime);
             cam.transform.rotation = Quaternion.Euler(0, 45, 0);
             StopCoroutine(camMovement);
             yield return null;
         }