My object is Null Reference Exception

Hello, when I choose my player in this case a helicopter and I give it in build the helicopter goes to the other scene of the game correctly the problem is when I restart my game scene with play again, it is destroyed because it is no longer null and I do not know how to return it to instantiate in the game scene

this is my script

 {
      private Helicopter _helicopterInstance;

      public Helicopter HelicopterInstance
      {
          get => _helicopterInstance;
          set => _helicopterInstance = value;
      }
      private HelicopterPlayerBuilder _helicopterPlayerBuilder;
      [SerializeField] private Helicopter _helicopter;
      
     [SerializeField] private Fuselage _fuselage1;
     [SerializeField] private Fuselage _fuselage2;
     [SerializeField] private Fuselage _fuselage3;

   

     [SerializeField] private Button _fuselage1Button;
     [SerializeField] private Button _fuselage2Button;
     [SerializeField] private Button _fuselage3Button;

     [SerializeField] private Button _startGameButton;
     [SerializeField] private GameObject startGameButtonGO;
     
     
     private void Awake()
     {
         _helicopterPlayerBuilder = new HelicopterPlayerBuilder();
         _helicopterPlayerBuilder.FromHelicopterPrefab(_helicopter);
         
         _fuselage1Button.onClick.AddListener(Fuselage1Pressed);
         _fuselage2Button.onClick.AddListener(Fuselage2Pressed);
         _fuselage3Button.onClick.AddListener(Fuselage3Pressed);
         
         startGameButtonGO.SetActive(false);
         _startGameButton.onClick.AddListener(StartGamePressed);

     }
     private void StartGamePressed()
     {
         SceneManager.LoadScene("FreeMode");
         Debug.Log("presionado");
     }
     
     //I BELIEVE IN THIS BUILD() IS THE PROBLEM
     public void Build()
     {
         startGameButtonGO.SetActive(true);

         //Checamos que mi instancia del helicoptero no sea nula
         if (_helicopterInstance != null)
         {
             Destroy(_helicopterInstance.gameObject);
         }
         _helicopterInstance = _helicopterPlayerBuilder.Build();

         DontDestroyOnLoad(_helicopterInstance);
     }
     
     //Fuselage
     private void Fuselage1Pressed()
     {
         _helicopterPlayerBuilder.withFuselage(_fuselage1);
         Build();
     }
     
     private void Fuselage2Pressed()
     {
         _helicopterPlayerBuilder.withFuselage(_fuselage2);
         Build();
     }
     private void Fuselage3Pressed()
     {
         _helicopterPlayerBuilder.withFuselage(_fuselage3);
         Build();

     }
 }

}