a simple generic singleton class for unity

Singleton.cs

using UnityEngine;

public class Singleton<T> : MonoBehaviour where T : MonoBehaviour
{
  protected bool Persists { get; set; }
  protected bool PreventDuplicates { get; set; }

  public static T Instance { get; private set; }
  
  protected virtual void Awake()
  {
    if (Instance == null)
    {
      Instance = this as T;
    }
    else if (Instance != null && Instance != this)
    {
      if (PreventDuplicates)
      {
        Destroy(Instance.gameObject);
      }
      
      Instance = this as T;
    }
    
    if (Persists)
    {
      DontDestroyOnLoad(gameObject);
    }
  }
}