revival/game/Assets/Scripts/UI/BootFlowUI.cs

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class BootFlowUI : MonoBehaviour
{
    [Header( "Timings" )] 
    [SerializeField]
    private float _fadeTime;
    
    [SerializeField]
    private float _holdTime;
    
    [SerializeField]
    private float _interFadeTime;
    
    [Header("References")]
    [SerializeField]
    private List<CanvasGroup> _fadeGroups;

    [SerializeField]
    private SceneLoader _loader;

    private void Start()
    {
        StartCoroutine( Flow() );
    }

    private IEnumerator Flow()
    {
        float a = 0.0f;
            
        for ( int i = 0; i < _fadeGroups.Count; ++i )
        {
            _fadeGroups[ i ].alpha = 0;
        }
        
        for ( int i = 0; i < _fadeGroups.Count; ++i )
        {
            a = 0f;
            while ( a < 1f )
            {
                a += Time.unscaledDeltaTime / _fadeTime;
                _fadeGroups[ i ].alpha = a;
                yield return null;
            }

            _fadeGroups[ i ].alpha = 1f;
            yield return new WaitForSecondsRealtime(_holdTime);
            
            a = 1f;
            while ( a > 0f )
            {
                a -= Time.unscaledDeltaTime / _fadeTime;
                _fadeGroups[ i ].alpha = a;
                yield return null;
            }

            _fadeGroups[ i ].alpha = 0f;
            
            yield return new WaitForSecondsRealtime(_interFadeTime);
        }
        
        yield return null;
        _loader.LoadScene( SceneType.MainMenu );
    }
}