If you are looking to create a DataTable, the following might work:

DataTable newTable = new DataTable();

if (result.Any())
{
    // Assume all rows have the same structure, use the first to create the columns
    var rowForColStructure = result.OfType<GLWebService.goldlasso.anyTypeArray1>().First();

    // Create the structures with a generic name
    DataColumn[] columns = rowForColStructure.item.Select((item, index) => new DataColumn(string.Format("Column{0}", index), item.GetType())).ToArray();
    // Add the columns to the table                
    newTable.Columns.AddRange(columns);
    
    // New rows get added when the query is executed via the ToList
    var rows = result.OfType<GLWebService.goldlasso.anyTypeArray1>().Select(item => newTable.Rows.Add(item.item)).ToList();
}

The items would still be in their original types. If you need it as strings, change it to:

DataTable newTable = new DataTable();

if (result.Any())
{
    // Assume all rows have the same structure, use the first to create the columns
    var rowForColStructure = result.OfType<GLWebService.goldlasso.anyTypeArray1>().First();

    // Create the structures with a generic name
    DataColumn[] columns = rowForColStructure.item.Select((item, index) => new DataColumn(string.Format("Column{0}", index), typeof(string))).ToArray();
    // Add the columns to the table                
    newTable.Columns.AddRange(columns);
    
    // New rows get added when the query is executed via the ToList
    var rows = result.OfType<GLWebService.goldlasso.anyTypeArray1>().Select(item => newTable.Rows.Add(item.item)).ToList();
}