how do i make an inventory system based on lists

So i have been trying to make an list based inventory system in Unity 2D (something like in enter the gungeon) for past 4 weeks and i have enough.

This is main thing that i atatch to player character (btw this code is from a answer by @niiicolai on another post )

The issues i have been having are as followes:

-can pick up things and put it into a list but i spawn all werpons and not only 1 that is equipped rn.

-have difficulties with finding gameobject with itemPickupScript (scripts find pickup once and then stops finding other pickups, which leads to me being unable to get other werpons than 1 thats get found first)

     using System.Collections;
     using System.Collections.Generic;
     using UnityEngine;
     
     public class InteractionMenager : MonoBehaviour
     {
         public KeyCode pickupKey = KeyCode.E;
         public KeyCode dropKey = KeyCode.G;
      
         public List<GameObject> weapons;
         public int maxWeapons = 2;
     
         public GameObject currentWeapon;
         public Transform hand;
         public Transform dropPoint;
     
     
         [Header("detection parameters")]
         public Transform detectionPoint;
         private const float detectionRadius = 0.2f;
         public LayerMask detectionlayer;
         public GameObject interactionObject;
     
         public GameObject ItemToAddPickup;
         public GameObject itemToAdd;
         
         void Update() {
     
             if(werponng.isReloading == true){
                 return;
             }
             // SELECT WEAPONS
             if (Input.GetKeyDown(KeyCode.Alpha1)) {
                 SelectWeapon(0);
             }
      
             if (Input.GetKeyDown(KeyCode.Alpha2)) {
                 SelectWeapon(1);
             }
     
             Vector2 Scalex4 = transform.localScale;
             Scalex4 *= 0.25f;
     
             ItemToAddPickup = GameObject.FindGameObjectWithTag("pickup");
     
             itemToAdd = ItemToAddPickup.GetComponent<itemPickupScript>().ItemToAdd;
     
             Vector2 werponposition = GameObject.Find("werponSlot").transform.position;
     
      
             // PICKUP WEAPONS
     
             if(DetectionObject()){
     
                 if (Input.GetKeyDown(pickupKey) && weapons.Count < maxWeapons) {
     
                     Debug.Log("working");
     
                     weapons.Add(itemToAdd);
     
                     GameObject ita = (GameObject)Instantiate(itemToAdd);
                  
                     ita.transform.parent = hand;
                     ita.transform.localScale = Scalex4;
                     ita.transform.position = werponposition;
     
                 }
             }
         }
     
     
         void SelectWeapon(int index) {
      
             // Ensure we have a weapon in the wanted 'slot'
             if(weapons.Count > index && weapons[index] != null) {                    
      
                 // Check if we already is carrying a weapon
                 if (currentWeapon != null) {
                     // hide the weapon                
                     currentWeapon.gameObject.SetActive(false);
                 }
      
                 // Add our new weapon
                 currentWeapon = weapons[index];
      
                 // Show our new weapon
                 currentWeapon.SetActive(true);            
             }
         }
     
     
     bool DetectionObject(){
     
             Collider2D obj = Physics2D.OverlapCircle(detectionPoint.position, detectionRadius, detectionlayer);
     
             if(obj==null){
     
                 interactionObject = null;
                 return false;
             }else{
                 interactionObject = obj.gameObject;
                return true;
             }
        }
     }

and i use this to get werpon from my pickup (which is another game object and i set the ItemToAdd in inspector to it)

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class itemPickupScript : MonoBehaviour
 {
     public GameObject ItemToAdd;
 }