Повторение: определяем добычу

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.InputSystem;

public enum Rarity { Common, Rare, Epic, Legendary }

[System.Serializable]
public class LootEntry
{
    public string itemName;
    public GameObject prefab;
    public Rarity rarity;
}

public class LootChest : MonoBehaviour
{
    public List<LootEntry> table;

    public int WeightOf(Rarity rarity)
    {
        switch (rarity)
        {
            case Rarity.Common: return 10;
            case Rarity.Rare: return 4;
            case Rarity.Epic: return 2;
            case Rarity.Legendary: return 1;
        }
        return 0;
    }

    public int TotalWeight()
    {
        int total = 0;
        foreach (LootEntry entry in table) total += WeightOf(entry.rarity);
        return total;
    }

    // Здесь должны быть Pick(int roll) и открытие сундука по нажатию Space
}