Instantiating Prefab at MousePosition & GUI.Matrix

Hello,

I was able to get an object to instantiate at the mouse position correctly before I added a GUI Matrix to keep the GUI scale. This is the code I was using.

             Screen.showCursor = false;
             Rect pos = new Rect(mousePos.x, Screen.height - mousePos.y ,turretCanPlace.width, turretCanPlace.height);
             GUI.Label(pos, mineCanPlace);    
             
             // If the player pressed LMB, instatiate the turret
             if(Input.GetMouseButton(0))
             {
                 Vector3 worldPos = Camera.main.ScreenToWorldPoint(mousePos);
                 worldPos.y -= 65.8f;
                 Debug.Log("TurretSceneScript.OnGui(Placing turret) World Pos: " + worldPos);
                 Instantiate(turretPrefab, worldPos, Quaternion.identity); //AngleAxis(90, Vector3.up));
                 
                 // Set the cursor back to visible
                 Screen.showCursor = true;
             }

When I added the GUI Matrix, the prefab no longer instantiated at the correct position. Here is the code for the GUI.Matrix. It's resizing from 1920 * 1080.

 public static void AutoResize(int screenWidth, int screenHeight)
     {
         Vector2 resizeRatio = new Vector2((float)Screen.width / screenWidth, (float)Screen.height / screenHeight);
         GUI.matrix = Matrix4x4.TRS(Vector3.zero, Quaternion.identity, new Vector3(resizeRatio.x, resizeRatio.y, 1.0f));
     }

I messed around with the code, and got a partial fix, but as I move the cursor to the right, or down, the distance between the icon and instantiated prefab increases. Here's what I'm currently using:

 Rect pos = new Rect(mousePos.x * (1920/Screen.width), (1080/Screen.height) * (Screen.height - mousePos.y) ,turretCanPlace.width, turretCanPlace.height);

Can anyone help me figure out how to get the prefab to instantiate on the correct location? Thanks for your help!