Startup.cs

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseUmbraco()
        .WithMiddleware(u =>
        {
            u.UseBackOffice();
            u.UseWebsite();
        })
        .WithEndpoints(u =>
        {
            u.EndpointRouteBuilder.MapControllerRoute(
                "BlogsByYear",
                "/blog",
                new { Controller = "Blog", Action = "Index" });

            u.EndpointRouteBuilder.MapControllerRoute(
                "BlogsByYear",
                "/blog/{year}",
                new { Controller = "Blog", Action = "BlogsByYear" });

            u.EndpointRouteBuilder.MapControllerRoute(
                "BlogsByYear",
                "/blog/{year}/{month}",
                new { Controller = "Blog", Action = "BlogsByYearAndMonth" });
        });
  }