Why does my mouselook sensitivity change depending on resolution? (C#)

I have this problem, I decided to build me game to see what it would look like, and I came across a problem, the mouse sensitivity changes depending on resolution, when on the lowest settings, it's too sensitive and on the highest settings it's not sensitive enough.

No errors or warnings display in the editor or on the built game.

How do I fix this?

If it helps, here's my code:

     public enum rotationAxis {MouseX = 1, MouseY = 2}
     public rotationAxis RotXY = rotationAxis.MouseX | rotationAxis.MouseY;
     
     // X Axis
     public float sensitivityX = 400f;
     public float minimumX = -360f;
     public float maximumX = 360f;
     private float rotationX = 0f;
     
     //Y Axis
     public float sensitivityY = 400f;
     public float minimumY = -50f;
     public float maximumY = 50f;
     private float rotationY = 0f;
     
     public Quaternion originalRotation;
     
     // Use this for initialization
     void Start () 
     {
         originalRotation = transform.localRotation;
     }
     
     // Update is called once per frame
     void Update () 
     {
         if (RotXY == rotationAxis.MouseX)
         {
             rotationX += Input.GetAxis("Mouse X") * sensitivityX * Time.deltaTime;
             rotationX = ClampAngle(rotationX, minimumX, maximumX);
             Quaternion xQuaternion = Quaternion.AngleAxis(rotationX, Vector3.up);
             transform.localRotation = originalRotation * xQuaternion;
         }
         if (RotXY == rotationAxis.MouseY)
         {
             rotationY -= Input.GetAxis("Mouse Y") * sensitivityY * Time.deltaTime;
             rotationY = ClampAngle(rotationY, minimumY, maximumY);
             Quaternion yQuaternion = Quaternion.AngleAxis (rotationY, Vector3.right);
             transform.localRotation = originalRotation * yQuaternion;
         }
     }
     public static float ClampAngle (float Angle, float Min, float Max)
     {
         if (Angle < -360)
         {
             Angle += 360;
         }
         if (Angle > 360)
         {
             Angle -= 360;
         }
         return Mathf.Clamp(Angle, Min, Max);
     }
 }