this is by @mjwills
it works.

var zipName = $"archive-{DateTime.Now:yyyy_MM_dd-HH_mm_ss}.zip";
        var folder = "D:\\xxdd";
        using var memoryStream = new MemoryStream();
        using (var zipArchive = new ZipArchive(memoryStream, ZipArchiveMode.Create, true))
        {
            var files = Directory.GetFiles(folder);
            foreach (var file in files)
            {
                zipArchive.CreateEntryFromFile(file, Path.GetFileName(file));
            }
        }

        File.WriteAllBytes(zipName, memoryStream.ToArray());
        Console.WriteLine("Hello, World!");