using System.Collections.Generic;

using System.Text.Json;

using System;

public class Program

{

    public static void Main()

    {

        var obj1 = new

        {

            item1 = 1

        };

        var obj2 = new

        {

            item2 = 2

        };

        List<JsonDocument> array = new();

        array.Add(JsonDocument.Parse(JsonSerializer.SerializeToUtf8Bytes(obj1, obj1.GetType())));

        array.Add(JsonDocument.Parse(JsonSerializer.SerializeToUtf8Bytes(obj2, obj2.GetType())));

        Console.Write(JsonSerializer.Serialize(array));

    }

}