ParallaxLayer.cs

using UnityEngine;

public class ParallaxLayer : MonoBehaviour
{
    [SerializeField] [Tooltip("Leave empty to automatically grab the camera.")] private Transform _followTransform;
    [Space]
    [SerializeField] private Vector3 movementScale = new Vector3(2f, 1f, 1f);
    [SerializeField] private Vector3 offsetPosition = new Vector3(0f, 0f, 0f);
    [SerializeField] [Tooltip("Manually set the offset or check this box to work it out automatically.")] private bool autoOffset;
    [Space]
    [SerializeField] private bool axisXDisabled = false;
    [SerializeField] private bool axisYDisabled = true;
    [SerializeField] private bool axisZDisabled = true;
    [Space]
    [SerializeField] private bool parallaxDisabled;

    private Vector3 _originalPosition;
    private Vector3 _moveToPosition;

    private float _xPosition;
    private float _yPosition;
    private float _zPosition;

    private void Start()
    {
        if (!_followTransform) { _followTransform = Camera.main.transform; }
        if (autoOffset) { offsetPosition = transform.position - _followTransform.position; }
        _originalPosition = transform.position;
    }

    private void LateUpdate()
    {
        if (parallaxDisabled) { return; }

        if (axisXDisabled) { _xPosition = _originalPosition.x; }
        else { _xPosition = _followTransform.position.x + offsetPosition.x; }

        if (axisYDisabled) { _yPosition = _originalPosition.y; }
        else { _yPosition = _followTransform.position.y + offsetPosition.y; }

        if (axisZDisabled) { _zPosition = _originalPosition.z; }
        else { _zPosition = _followTransform.position.z + offsetPosition.z; }

        _moveToPosition = Vector3.Scale(new Vector3(_xPosition, _yPosition, _zPosition), movementScale);
        transform.position = _moveToPosition;
    }
}