C# Need Help Refining Ricochet Script

I've added a ricochet function to my script. But the script doesn't ricochet like I was expecting it to. My logic with the ricochet is that when the 2d projectile collides with a gameobject it rotates along the z axis minus the other gameobject's transform.rotation.z to have it look like it ricocheted off the gameobject. However for some reason the projectile always rotates upward no matter what other's transform.rotation.z is. Is there a flaw with the logic to my script?

 public float speed;
 public bool ricochet;
 
         void Update () 
         {
              rigidbody2D.velocity = transform.up * speed; 
             }
     
     void OnTriggerEnter2D(Collider2D other)
         {
             if(ricochet == true){
                transform.rotation = Quaternion.Euler(0,0,transform.rotation.z - other.transform.rotation.z);
             }
         }