How to access a bool from buttonclick scr. into another script

hey at all,
i 've made a menu with buttons with which the player shall be able to upgrade settings like the damage strength of a laser projectile if he has enough points. So i made a Canvas = MyCanvas and attached the script "Spielende" in the OnClick() in the editor. To the Laserprojectile Upgrade button i set the function "Spielende.Stufe_1_Upgrade" in which a bool "Stufe_1_done = false" is changed to true if the player upgrades ( clicked button) the L_projectile. All this works well in the menu or if the buttons are clicked.
But how can i get it in the Script attached to the projectile prefab ? i tried to access it the classical way but that doesnt work.

here's the function in the script : Spielende

         public void Stufe_1_Upgrade()
         {
                 if(Stufe_1_done == true)
                 {
                         return;
                 }
                 else
                 {
                         if(Energy_Laser_Upgr_St_1.activeSelf && punktescript.Player_currentPlayerPoints >= Stufe_1 && Stufe_1_done == false)
                         {
                                 punktescript.Player_currentPlayerPoints -= Stufe_1;
                                 Stufe_1_done = true;
                         }
                         if(Stufe_1_done == true && Energy_Laser_Upgr_St_1.activeSelf)
                         {
                                 Energy_Laser_Upgr_St_1.SetActive(false)    ;
                         }
                 }
         }  

here's my script which is attached to the laser projectile in which i want to reset the value for damage
if the button is clicked

 public class LaserProjectile : MonoBehaviour 
 {
     public float speed = 2f;
     public int damage = 25;
     private Transform thisTransform;
         //public Spielende thisscr;
         //public GameObject thiscanvas;
     //public Transform laserHitFXPrefab;
 
     // Use this for initialization
     void Start () 
     {
         thisTransform = transform;
     }
     
     // Update is called once per frame
     void Update () 
     {
         thisTransform.position += Time.deltaTime * speed * thisTransform.forward;
     }
 
 
                 
     void OnCollisionEnter(Collision collision)
     {
         if (collision.gameObject.tag == "Enemy") 
         {
                 collision.gameObject.SendMessage ("TakeDamage", damage, SendMessageOptions.DontRequireReceiver);
 
                 ContactPoint contact = collision.contacts[0];
                 Quaternion rot = Quaternion.FromToRotation(Vector3.up, contact.normal);
                 Vector3 pos = contact.point;
                 //Instantiate (laserHitFXPrefab, pos, rot );
                 Destroy (gameObject);
         }
 
 
         if (collision.gameObject.tag == "Asteroid")     
         {
                 collision.gameObject.SendMessage("TakeDamage", damage,SendMessageOptions.DontRequireReceiver);
 
                 ContactPoint contact = collision.contacts [0];
                 Quaternion rot = Quaternion.FromToRotation (Vector3.up, contact.normal);
                 Vector3 pos = contact.point;
                 
                 Destroy (gameObject);
         }
     }
 }  

this prob is pretty new to me because i've just started working with menus
thx previously ( hope so much it isnt to complicated) :)
yours