Shooting was slow and dont know whats the best way to add sound and muzzle flash so no delay occur

i am using Camera.main.ScreenToWorldPoint to get touch position and then use lookat function to Look at touch position and then fite rocket at touch position . My code is working but it little laggy , Plz anyone help m to optimize my code . or show me a way how to fire and play sound and flash simultaneously without delay . here is my code

void FixedUpdate() { int fingerCount = 0; foreach (Touch touch in Input.touches) { if (touch.phase == TouchPhase.Began || touch.phase != TouchPhase.Ended && touch.phase != TouchPhase.Canceled && touch.phase != TouchPhase.Moved && touch.phase != TouchPhase.Stationary) fingerCount++;

         if (fingerCount > 0)
         {

             worldPos = Camera.main.ScreenToWorldPoint(touch.position);
          
            Vector2 touchPos = new Vector2(worldPos.x, worldPos.y);
             barrelEnd.LookAt(touchPos);

             //  Debug.DrawRay(touch.position, touchPos, Color.red);



             Rigidbody2D rocketInstance;
             rocketInstance = Instantiate(SpherePrefab, worldPos, Quaternion.identity) as Rigidbody2D;
             rocketInstance.velocity = (barrelEnd.forward * 7000);
             audioSource.Play();
             if (MuzzleFlashPrefab)
             {
                 var flash = (GameObject)Instantiate(MuzzleFlashPrefab, barrelEnd.position, Quaternion.identity);
                 flash.transform.parent = transform;
             }
         
             if (touchPos.x > 0 && !facingRight)
                 Flip();
             if (touchPos.x < 0 && facingRight)
                 Flip();



         }
     }
 }
 void Flip()
 {
     facingRight = !facingRight;
     Vector3 theScale = transform.localScale;     //    Fliping player to avoid left and righ animation .
    theScale.x *= -1;
     transform.localScale = theScale;

} }