Using dependency Injection in .Net Core 6

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using static System.Guid;

namespace myWatchList
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //setup our DI
            var serviceProvider = new ServiceCollection()
                .AddLogging(c => c.AddConsole(opt => opt.LogToStandardErrorThreshold = LogLevel.Debug))
                .AddSingleton<IFooService, FooService>()
                .AddSingleton<IBarService, BarService>()
                .BuildServiceProvider();
                        
            //configure console logging
            serviceProvider
                .GetService<ILoggerFactory>();
          
            var logger = serviceProvider.GetService<ILoggerFactory>()
                .CreateLogger<Program>();
            logger.LogInformation("Starting application");

            //do the actual work here
            var bar = serviceProvider.GetService<IBarService>();
            bar.DoSomeRealWork();

            logger.LogDebug("All done!");
        }
    }

    public interface IFooService
    {
        void DoThing(int number);
    }

    public interface IBarService
    {
        void DoSomeRealWork();
    }
    public class BarService : IBarService
    {
        private readonly IFooService _fooService;
        public BarService(IFooService fooService)
        {
            _fooService = fooService;
        }

        public void DoSomeRealWork()
        {
            for (int i = 0; i < 10; i++)
            {
                _fooService.DoThing(i);
            }
        }
    }

    public class FooService : IFooService
    {
        private readonly ILogger<FooService> _logger;
        public FooService(ILoggerFactory loggerFactory)
        {
            _logger = loggerFactory.CreateLogger<FooService>();
        }

        public void DoThing(int number)
        {
            _logger.LogInformation($"Doing the thing {number}");
        }
    }

}