Rotating Camera around Player's X-axis while rotating Player around its Y-axis (using mouse input)

Dear community,

I have been trying to implement a third-person experience to learn Unity development. To get to the point:

I have the following structure within the Player GameObject:

• Structure (3d shapes)

• Colliders (Colliders from Structure copied over, but with 'Is Trigger' false)

• Main Camera

So the camera 'follows' the Player as it's a child of it.

Now for the Rotation code:

 public float sensitivityX = 15F;
 public float sensitivityY = 15F;
 public float minimumX = -360F;
 public float maximumX = 360F;
 public float minimumY = 20F;
 public float maximumY = -20F;
 float rotationY;

 Camera Camera;

 void Start()
 {
     Cursor.visible = false;
     Camera = GetComponentInChildren<Camera>();
 }

 void FixedUpdate()
 {
     float rotationX = transform.localEulerAngles.y + Input.GetAxis("Mouse X") * sensitivityX;

     float newRotationY = this.rotationY + Input.GetAxis("Mouse Y") * sensitivityY;

     newRotationY = Mathf.Clamp(newRotationY, minimumY, maximumY);

     float rotationY = this.rotationY - newRotationY;

     this.rotationY = newRotationY;

     Camera.transform.RotateAround(transform.position, new Vector3(1, 0, 0), rotationY);

     transform.localEulerAngles = new Vector3(0, rotationX, 0);
 }

I borrowed some code from here, but what happens now is that the Camera moves around the Z-Axis aswell and I can't figure out why. What I would want to happen is that the Camera only rotates around the Player's X-axis using the rotationY value and that the Player only rotates around its own Y-axis.

Commenting out either rotation works fine by itself, but combining them results in interesting rotations...

Thanks in advance for any help!