using System;

using System.Globalization;

using System.Reflection;

using System.ComponentModel;

​

public class Program

{

    public static void Main()

    {

        var sdate = "2021-04-14T00:00:00+00:00";

        //Aqui talvez deveria colocar o -3 por ser ptB

        var date = DateTime.Parse(sdate, CultureInfo.GetCultureInfo("pt-BR"));

        Console.WriteLine(date.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture));

        Console.WriteLine(date.ToString("yyyy-MM-dd", CultureInfo.GetCultureInfo("pt-BR")));

    }

}