How to have free rotation camera?

Hi Unity Answers

So I'm trying to create an RTS style camera using the Camera linked to a Camera Rig. Included in this will be the option for the user to move around using WASD / arrows and rotate using Q&E. However, I also want to give the user the option to go into a sort of "free look" mode whenever they click and hold the scroll wheel (Mouse 2). I think the Q&E rotate and scroll wheel free look are conflicting as when I added the Q&E rotate option to my code, whenever I try playing in the scene, the free look always snaps back to the X axis rotation it began with.

It's worth pointing out that I'm relatively new to C# so I think the issue is me not understanding the Quaternion concept (last line of code) as when I // that out of the code, the Q&E keys no longer rotate, the camera but free look mode works perfectly. Any help or signposting would be greatly appreciated!

Here's the code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class CameraController : MonoBehaviour
 {
     public float normalSpeed;
     public float fastSpeed;
     public float movementSpeed;
     public float movementTime;
     public float rotationAmount;
 
     public Vector3 newPosition;
     public Quaternion newRotation;
 
     public float freeLookSensitivity = 3f;
     private bool looking = false;
 
 
 
     // Start is called before the first frame update
     void Start()
     {
         newPosition = transform.position;
         newRotation = transform.rotation;
     }
 
     // Update is called once per frame
     void Update()
     {
         HandleMovementInput();
 
         if (looking)
         {
             float newRotationX = transform.localEulerAngles.y + Input.GetAxis("Mouse X") * freeLookSensitivity;
             float newRotationY = transform.localEulerAngles.x - Input.GetAxis("Mouse Y") * freeLookSensitivity;
             transform.localEulerAngles = new Vector3(newRotationY, newRotationX, 0f);
         }
 
         float axis = Input.GetAxis("Mouse ScrollWheel");
 
         if (Input.GetKeyDown(KeyCode.Mouse2))
         {
             StartLooking();
         }
         else if (Input.GetKeyUp(KeyCode.Mouse2))
         {
             StopLooking();
         }
 
 
     }
 
     void OnDisable()
     {
         StopLooking();
     }
 
     public void StartLooking()
     {
         looking = true;
         Cursor.visible = false;
         Cursor.lockState = CursorLockMode.Locked;
     }
 
     public void StopLooking()
     {
         looking = false;
         Cursor.visible = true;
         Cursor.lockState = CursorLockMode.None;
     }
 
     void HandleMovementInput()
     {
         if(Input.GetKey(KeyCode.LeftShift) || Input.GetKey(KeyCode.RightShift))
         {
             movementSpeed = fastSpeed;
         }
 
         else
         {
             movementSpeed = normalSpeed;
         }
 
         if(Input.GetKey(KeyCode.W) || Input.GetKey(KeyCode.UpArrow))
         {
             newPosition += (transform.forward * movementSpeed);
         }
 
         if(Input.GetKey(KeyCode.S) || Input.GetKey(KeyCode.DownArrow))
         {
             newPosition += (transform.forward * -movementSpeed);
         }
 
         if(Input.GetKey(KeyCode.D) || Input.GetKey(KeyCode.RightArrow))
         {
             newPosition += (transform.right * movementSpeed);
         }
 
         if(Input.GetKey(KeyCode.A) || Input.GetKey(KeyCode.LeftArrow))
         {
             newPosition += (transform.right * -movementSpeed);
         }
 
         if(Input.GetKey(KeyCode.Q))
         {
             newRotation *= Quaternion.Euler(Vector3.up * rotationAmount);
         }
 
         if (Input.GetKey(KeyCode.E))
         {
             newRotation *= Quaternion.Euler(Vector3.up * -rotationAmount);
         }
 
         transform.position = Vector3.Lerp(transform.position, newPosition, Time.deltaTime * movementTime);
         transform.rotation = Quaternion.Lerp(transform.rotation, newRotation, Time.deltaTime * movementTime);
 
     }
 }