Lean/Peak system

Hey people, so im trying to do a lean/peak system like the one we see in Rainbow Six Siege, i have an idea on how to do this but i am unable to execute it… I have a script for my character, and one for my character camera, Here is how much camera is looking…

     // Update is called once per frame
     void Update()
     {
         CameraRotation();
         if (Input.GetKey(KeyCode.Q))
         {
             isLeaningLeft = true;
 
             transform.Rotate(0, 0, -10 * Time.deltaTime);
         }
         else
         {
             isLeaningLeft = false;
         }
 
         if (Input.GetKey(KeyCode.E))
         {
             isLeaningRight = true;
             print("Leaning Right");
         }
         else
         {
             isLeaningRight = false;
         }
     }

I also store the initial position of the camera so that i can later return to it

     Transform playerCamera;
 
     Vector3 initPos;
 
     Quaternion initRot;
 
     bool isLeaningLeft;
     bool isLeaningRight;
 
 
     // Start is called before the first frame update
     void Start()
     {
         //This doesn't matter here..
         //LockCursor();
         //xAxisClamp = 0;
 
         initPos = playerCamera.localPosition;
         initRot = playerCamera.localRotation;
     }

So this obviously doesn't work, and i understandw why it doesnt. Do i need to use quaternion or euer angles? If anyone could point me in the right direction it would be really appreciated, thanks.