SQLServer bulkCopy.cs

using var bulkCopy = new SqlBulkCopy(
    _connection,
    SqlBulkCopyOptions.TableLock |
    SqlBulkCopyOptions.FireTriggers |
    SqlBulkCopyOptions.UseInternalTransaction,
    null
    );

bulkCopy.DestinationTableName = "table";
bulkCopy.BatchSize = 150_000;
bulkCopy.BulkCopyTimeout = TimeSpan.FromMinutes(60).Seconds;

var propNames = records.FirstOrDefault().GetPropertiesOf();

foreach (var prop in propNames)
    bulkCopy.ColumnMappings.Add(prop, prop);

var dataTable = records.ToDataTable(); // morelinq

await bulkCopy.WriteToServerAsync(dataTable);
            
            
public static IEnumerable<string> GetPropertiesOf<T>(this T _)
{
    var props = typeof(T)
        .GetProperties(BindingFlags.Public | BindingFlags.Instance)
        .Select(x => x.Name)
        .ToList();

    return props;
}