Unity scene transition – original background does not appear

1. In the scene named Stage1, the Player moves to the scene named Stage1_1 through a Gate.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;

public class ChangeSceneOnTag : MonoBehaviour
{
    private void OnTriggerEnter2D(Collider2D other)
    {
        // When it contacts an object with the "Star" tag
        if (other.CompareTag("Star"))
        {
            LoadStage1_1Scene();
        }
    }

    void LoadStage1_1Scene()
    {
        SceneManager.LoadScene("Stage1_Scene 1");
    }
}

2. From Stage1_1, the Player moves to a specific SpawnPoint in Stage1 through another Gate.

using UnityEngine;
using UnityEngine.SceneManagement;

public class ChangeSceneOnTag2 : MonoBehaviour
{
    private void Start()
    {

    }

    private void OnTriggerEnter2D(Collider2D other)
    {
        // When it contacts an object with the "Gate" tag
        if (other.CompareTag("Gate"))
        {
            LoadStage1Scene();
            // Register a method to be called when the scene load is completed
            SceneManager.sceneLoaded += OnSceneLoaded;
        }
    }

    void LoadStage1Scene()
    {
        SceneManager.LoadScene("Stage1_Scene");
    }

    void OnSceneLoaded(Scene scene, LoadSceneMode mode)
    {
        if (scene.name == "Stage1_Scene")
        {
            GameObject player = GameObject.FindGameObjectWithTag("Player");
            GameObject spawnPoint = GameObject.Find("SpawnPoint");

            if (player != null && spawnPoint != null)
            {
                player.transform.position = spawnPoint.transform.position;

                Camera mainCamera = Camera.main;
                if (mainCamera != null)
                {
                    mainCamera.transform.position = new Vector3(spawnPoint.transform.position.x, spawnPoint.transform.position.y, mainCamera.transform.position.z);
                }

                // Reset the ParallaxBackground.
                ResetParallaxBackground();
            }

            // Remove this event handler as it's no longer needed.
            SceneManager.sceneLoaded -= OnSceneLoaded;
        }
    }

    void ResetParallaxBackground()
    {
        ParallaxBackground[] parallaxBackgrounds = FindObjectsOfType<ParallaxBackground>();
        foreach (var bg in parallaxBackgrounds)
        {
            bg.ResetBackground(Camera.main.transform.position);
        }
    }
}

The issue I’m facing is with the Background. I have a code named ParallaxBackground.cs.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ParallaxBackground : MonoBehaviour
{
    public Transform cameraTransform;
    public float parallaxSpeed = 0.5f; // Adjust the value between 0 and 1 to change the degree of movement.
    private Vector3 lastCameraPosition;

    void Start()
    {
        lastCameraPosition = cameraTransform.position;
    }

    void Update()
    {
        Vector3 deltaMovement = cameraTransform.position - lastCameraPosition;
        transform.position += new Vector3(deltaMovement.x * parallaxSpeed, deltaMovement.y * parallaxSpeed, 0f);
        lastCameraPosition = cameraTransform.position;
    }

public void ResetBackground(Vector3 newCameraPosition)
    {
        lastCameraPosition = newCameraPosition;
    }
}

However, when moving to the specific SpawnPoint in Stage1, this code does not function. As a result, the original background of Stage1 does not appear. How do I solve it?

Stage1 -> Stage1_1 -> SpawnPoint in Stage1 ==> Scene transition is OK.
However, ParallaxBackground.cs associated with the scene transition does not work.
The Player moved to the SpawnPoint, but the background did not follow him.