Persistent GameManager and object Instantiation

What I'm trying to do is to make the GameManager object persistent between scenes, reading a bit I realized that the DontDestroyOnLoad() method allows this behavior, however I don't understand why it doesn't allow me to instantiate objects in new scenes. The following code perfectly replicates the main problem:

 using UnityEngine;
 using UnityEngine.SceneManagement;
 
 public class GameManager : MonoBehaviour
 {
     public GameObject objectPrefab;
     private void Awake()
     {
         DontDestroyOnLoad(gameObject);
     }
     private void Update()
     {
         if (Input.GetKeyDown(KeyCode.Space))
         {
             SceneManager.LoadScene("Scene2");
             GameObject instance = Instantiate(objectPrefab);
         }
     }
 }