How do I get intro dialog box to be destroyed after playing once?

Hello! I'm new to Unity and somewhat new to coding in general. I'm making a simple 2D 16bit rpg game. I would like an intro dialog box to play once the player loads in, then for the 2d trigger box to be destroyed so it never plays again. I have dialog working for interactable objects, but for some reason my "IsIntroductionRequired" feature/function is not working or doing anything. Funnily enough, it worked once when I first wrote it. However, it hasn't worked and I have no clue why!

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.SceneManagement; 
 
 public class DialogActivator : MonoBehaviour
 {
 
     // array of dialog lines
     public string [] lines;
 
     private bool canActivate;
 
     private const byte REQUIRED = 1;
     private const byte NOT_REQUIRED = 0;
     private const string PP_KEY_INTRO_REQUIRED = "IntroRequired";
 
     public GameObject dialog;
 
     // Start is called before the first frame update
     void Start()
     {
     }
 
     // Update is called once per frame
     void Update()
     {
         // if dialog can be displayed and the button is pressed
         // and dialog box not active
         if(canActivate && Input.GetButtonDown("Read") && !DialogManager.instance.dialogBox.activeInHierarchy)
         {
             DialogManager.instance.ShowDialog(lines);
         }
     }
 
     // actiavtes dialog if player walks into dialog area
     private void OnTriggerEnter2D(Collider2D other)
     {
         if(other.tag == "Player")
         {
             canActivate = true;
 
             if (IsIntroductionRequired)
             {
                 IsIntroductionRequired = false;
                 DialogManager.instance.ShowDialog(lines);
                 Destroy(dialog.gameObject);
 
             }
         }
 
     }
 
     // deactiavtes dialog if player has already walked out of dialog area
     private void OnTriggerExit2D(Collider2D other)
     {
         if(other.tag == "Player")
         {
             canActivate = false;
         }
     }
         
     private bool IsIntroductionRequired
     {
         get { return PlayerPrefs.GetInt(PP_KEY_INTRO_REQUIRED, REQUIRED) == REQUIRED; }
         set { PlayerPrefs.SetInt(PP_KEY_INTRO_REQUIRED, value ? REQUIRED : NOT_REQUIRED); }
     }
 }
 

any helps is appreciated thanks <3