using System;

using System.Collections.Generic;

using System.Linq;

public class Test{

    public DateTime? dt {get;set;}

}

​

public class Program

{

    public static void Main()

    {

        var l = new List<Test>();

        l.Add(new Test{dt = new DateTime(2021, 12, 1, 0, 0, 0, DateTimeKind.Utc)});

        l.Add(new Test());

        l = null;

        if(l.Any(li => li.dt >= new DateTime(2021, 11, 1, 0, 0, 0, DateTimeKind.Utc))){

            Console.WriteLine("success");

        }

    }

}