Unity "void Main" OOP template

Program.cs

using System.Diagnostics;
using System.Threading.Tasks;
using UnityEngine;
using UnityEngine.SceneManagement;

namespace BananaParty.FurryGame.Client
{
    /// <summary>
    /// Entry point for wiring up the engine and executing main loop.
    /// </summary>
    public static class Program
    {
        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.AfterSceneLoad)]
        public static async void Main()
        {
            // Prevent Unity Test Framework from shitting itself.
#if UNITY_EDITOR
            if (SceneManager.GetActiveScene().name.StartsWith("InitTestScene"))
                return;
#elif UNITY_INCLUDE_TESTS
            return;
#endif

            // Start editor playmode from scene 0.
#if UNITY_EDITOR
            AsyncOperation sceneLoadingOperation = SceneManager.LoadSceneAsync(0);
            while (!sceneLoadingOperation.isDone)
                await Task.Yield();
#endif

            // Output Trace events, but don't duplicate them in a web export.
#if UNITY_EDITOR || !UNITY_WEBGL
            Trace.Listeners.Add(new UnityConsoleTraceListener
            {
                Filter = new EventTypeFilter(SourceLevels.Information)
            });
#endif

            bool quitting = false;
            Application.quitting += () => { quitting = true; };

            Stopwatch stopwatch = new();
            stopwatch.Start();

            using (var clientApplication = new ClientApplication(
                new UnityRenderLibrary(),
                new UnitySceneFactory(),
                new UnityUserInterfaceLibrary()))
            {
                while (!quitting)
                {
                    clientApplication.ExecuteFrame(stopwatch.ElapsedMilliseconds);
                    await Task.Yield();
                }
            }
        }
    }
}

Scenes are no longer the root of your project, nor the game code depends on Unity Engine.
Ripped directly out of personal project without modifications.