How to fix monobehavour-pickups together with class-copying

My problem is the following: I have a couple of classes(pots and other items) that inherit from my class items and override the use-function. This classes are not from monobehavour in order to be able to copy them with my copyconstructor. Now i want to make a script to make pickup-items in the scence, that adds the items to some inventory. How can i save the different classes flexible enough so i can still call the operwritten use(). The only idea I had was to make a Object-Array to save the classes leaving me unable to get the classes back once i saved them as object. I would be rly happy if someone would have some general idea how to work around this problem. I feel like i miss some basic knowledge... Anyway this are some of the more important scripts: a bit long but should not go into depth too much at all; thanks for your help guys :)

  using System; using System.Collections; using System.Collections.Generic; using UnityEngine;
  public class Item {
 string _name = "Demoname";
  public Player player;
  int _vkpreis = 1;
  int _kaufpreis = 2;
  int _maxstack = 1;//wieoft stackbar
  int _count = 1;
  private bool _onplayer = false;
 
  public Item(Item lastitem)
  {
      player = GameObject.FindGameObjectWithTag("Player").GetComponent<Player>();
      _name = lastitem.Itemname;
      _vkpreis = lastitem.Vkpreis;
      _kaufpreis = lastitem.Kaufpreis;
      _maxstack = lastitem.Maxstack;
      _count = lastitem.Count;
      _onplayer = lastitem.Onplayer;
  }
  public Item(bool onplayer)
  {//assign values
  }
  public Item()
  {//assign values
  }
  public Item(string itemname, int vkpreis, int kaufpreis, int maxstack, int count,bool onplayer)
  {
  
  }
 
  public virtual void Setup(string itemname, int vkpreis, int kaufpreis, int maxstack, int count,bool onplayer)   
  {
      player = GameObject.FindGameObjectWithTag("Player").GetComponent<Player>();
      _name = itemname;
      _vkpreis = vkpreis;
      _kaufpreis = kaufpreis;
      _maxstack = maxstack;
      _count = count;
      _onplayer = onplayer;
  }
  public  void Setup(Item item)
  {
      player = GameObject.FindGameObjectWithTag("Player").GetComponent<Player>();
      _name = item.Itemname;
      _vkpreis = item.Vkpreis;
      _kaufpreis = item.Kaufpreis;
      _maxstack = item.Maxstack;
      _count = item.Count;
      _onplayer = item.Onplayer;
  }
 
  public int Count
  {
      get { return _count; }
      set {
          if (value > _maxstack)
          {
              _count = _maxstack;
          }
          else if (value < 0)
          {
              _count = 0;
          }
          else
          {
              _count = value;
          }
         
      }
  }
  public virtual void Use() { }
  public int Maxstack
  {
      get { return _maxstack; }
      set { _maxstack = value; }
  }
  public int Kaufpreis
  {
      get { return _kaufpreis; }
      set { _kaufpreis = value; }
  }
  public int Vkpreis
  {
      get { return _vkpreis; }
      set { _vkpreis = value; }
  }
  public string Itemname
  {
      get { return _name; }
      set { _name = value; }
  }
  public bool Onplayer
  {
      get { return _onplayer; }
      set { _onplayer = value; }
  }
 
  

}

Then this is my HealPotion-Script for example

 public class LifePotion : Item
  public int healsize = 0
 public void Setup(string itemname, int vkpreis, int kaufpreis, int maxstack, int count,int healSize, bool onplayer) 
      {
          Itemname = itemname;
          Vkpreis = vkpreis;
          Kaufpreis = kaufpreis;
          Maxstack = maxstack;
          Count = count;
          healsize = healSize;
          Onplayer = onplayer;   
      }
  
 
  public override void Use()
  {
      if (Count > 0 && (player.curHealth < player.maxHealth))
      {
          player.Heal(healsize);
          Count = Count - 1;
      }
      
  }
  public void Start()
  {
      player = GameObject.FindGameObjectWithTag("Player").GetComponent<Player>();
      Itemname = "Redpot";
      Maxstack = 2;
      Count = 1;
      Vkpreis = 1;
      Kaufpreis = 2;
      healsize = 10;
  }

}

and my inventory script, i saved them as items for now:

 using System;
  using System.Collections;
  using System.Collections.Generic;
  using UnityEngine;
  
  public class Itemhandler : MonoBehaviour {
      public Item[] items = new Item[0];
  private void Start()
  {
      
  }
 
  public bool AddItem(Item item)
  {//returnt ob aufgehoben wird
      try
      {
          for (int i = 0; i < items.Length; i++)
      {
        
       
              if (item.Itemname == items[i].Itemname)
              {
                  if (items[i].Maxstack == items[i].Count)
                  {
                      items[i].Count = items[i].Count + item.Count;
                      return false;
                  }
                  else
                  {
                      // Debug.Log(items[i].Count.ToString() + item.Count.ToString() + item.Maxstack.ToString() + items[i].Maxstack.ToString() + item.Vkpreis.ToString());
                      items[i].Count = items[i].Count + item.Count;
                      return true;
                  }
              
               }
          }
          Resize(items.Length + 1, ref items);//???buggy when items emty, maybe try/catch useless lateron
          items[items.Length - 1] = new Item(item);
          Debug.Log("itemlen:" + items.Length);
          return true;
      }
      catch (Exception err)
          {
          //nothing
          Debug.Log("itemlen:" + items.Length);
          Debug.Log(err.Message);
          Resize(1, ref items);
          items[items.Length - 1] = new Item(item);
          return true;
      }
 
      
  }
  private void Resize(int Size, ref Item[] itemss)
  {
 
      Item[] temp = new Item[Size];
      for (int c = 1; c < Mathf.Min(Size, itemss.Length); c++)
      {
          temp[c] = new Item(itemss[c]);
      }
      itemss = temp;
  }
 
  public int Get_indexByName(string _name)
  {
      for (int i = 0; i < items.Length; i++)
      {
         if(items[i].Itemname == _name)
          {
              return i;
          }
      }
 
      return -1;
  }
 

}