Working with Items and Class Inheritance for an RPG Item Database

So I've been coming up with a plan on making an item database, and that is to make it a List of type Item.

public List<Item> items = new List<Item>();

I want to place all of my items, whether it is a weapon, a consumable, or a quest item onto a single database. I am using a serializable Item class to hold the common data, and then I have a Weapon, Consumable, and Quest class (which are all inherited to Item) so that they have their own individual variables.

 using UnityEngine;
 using UnityEngine.UI;
 using System.Collections;
 
 [System.Serializable]
 public class Item
 {
     public int itemID;
     public string itemName;
     public string itemDesc;
     public Image itemImage;
 
     public enum ItemType
     {
         None,
         Consumable,
         Quest
     }
     public ItemType itemType;
 }

And then a sample for the Consumable class would be

 using UnityEngine;
 using System.Collections;
 
 public class ItemConsumable : Item 
 {
     public int addHP;
     public int addMP;
 }

With the Item class serialized, I can edit each object in the database list via the inspector, but I am only able to edit variables in the Item class, and not on the child classes.

I was thinking of placing an enum to determine if the item is a weapon, a consumable, or etc,. Pop up an if statement and make Item as someItemType or whatever. This is probably wrong and I've done my research on attempting that.

Is there any other way for this?

NOTE: I will not be using XML.