How to store the position of an object at the start of a scene

Which script are you using to instantiate the object? I think you should be storing the position there before inactivating the first object and then instantiate the next object and pass the position.

 public GameObject firstObject; //game object that becomes inactive. Place the object on the field of the script in the inspector.
 public GameObject objectToInstantiate;
 Vector3 positionToSave;
 
 //if you want to store the position at the beginning, do it in the start method, but if the object moves, this is useless.
 void Start(){
 positionToSave = firstObject.transform.position;
 }
 
 void Update(){
 
 //you can save position before setting object to inactive
 positionToSave = firstObject.transform.position;
 firstObject.SetActive(false);
 Instantiate(objectToInstantiate);
 objectToInstantiate.transform.position = positionToSave;
 }

Is there a reason that you can’t do it this way??