the following Code after "yield return new WaitForSeconds();" not executed

Its like this, i have project, with some cool items. One of them is the Black Hole and another one is the "Hulk mode". The Black Hole reduce the time (with the Time.timeScale = 0.3f; command) too 0,3f and the Hulk Mode sets the size of the GameObject to a bigger Size and cant get hurt from Enemies. But when I integrate my Black Hole item in the Game the command "yield return new WaitForSeconds();" wont work anymore (or the following code after it). Does anyone have some ideas what went wrong? Tips for my Scritping Skills are Welcome too ;D

here's the Code for the Black Hole:

 public class SlowMotion : MonoBehaviour 
 {
     
 
     IEnumerator OnCollisionEnter2D (Collision2D collision) 
     {
 
         if(collision.gameObject.tag == "rocket")
         {
             Debug.Log("SlowMotion startet");
             Time.timeScale = 0.3f;
             yield return new WaitForSeconds(2f);
             Time.timeScale = 1.0f;
             Debug.Log("SlowMotion Ende");
         }
     }
 }
 
 

here the code for the Hulk Mode:

     public GameObject pickupEffect;
     public float mutliplier = 1.4f;
     public float scale;
     public float duration;
     protected float Counter;
     float trueornot;
     BoxCollider2D collider;
 
     protected void CountCounter()
     {
         Counter = trueornot;
     }
     void Start()
     {
         trueornot = 1f;
         
     }
     void OnTriggerEnter2D (Collider2D other)
     {
         
         if(other.CompareTag("rocket"))
         {
             
             StartCoroutine(Pickup(other));
 
         }       
     }
     
     private IEnumerator Pickup(Collider2D rocket)
     {
 
         Instantiate(pickupEffect, transform.position, transform.rotation);
         
         pickupEffect.transform.localScale = new Vector3(2,2,2);
         
         
         GetComponent<BoxCollider2D>().enabled = false;
         rocket.transform.localScale = new Vector3 (scale, scale, 1);
         
         rocket.gameObject.tag="Player"; 
         Debug.Log("1");
         yield return new WaitForSeconds(duration);
         Debug.Log("2");
         rocket.gameObject.tag="rocket"; 
         
         
         rocket.transform.localScale = new Vector3 (2, 2, 2);
         Destroy(this.gameObject);
     }
     
 }

I have a third Item, and with it I had some issues too, the position from the instantiated Objects were the same position where I collected the first Item. But this Issues got fixed by setting a "private" in front of the IEnumerator, maybe this comment is a help for the troubleshooting.

sincerely

Niklas