You can convert the DateTime to a Time String and send that in the insert or update strings.

Here is the Cache Class used in my example:

Class User.TestTimeData Extends %Persistent
{

Property TimeFormat As %String [ Required ];

Property TimeTest As %Time [ Required ];
}

Here is the C# .Net Core Console App code example:

using System;
using System.Data.Odbc;

namespace TestCacheTimeType
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
            DateTime dateTime = DateTime.MinValue.AddHours(22).AddMinutes(10);

            string timeLong = dateTime.ToLongTimeString();
            InsertRecord("ToLongTimeString", timeLong);

            string timeShort = dateTime.ToShortTimeString();
            InsertRecord("ToShortTimeString", timeShort);

            string timeFormatted = dateTime.ToString("HH:mm:ss");
            InsertRecord("ToString"HH:mm:ss)"", timeFormatted);

            Console.WriteLine("Press any key to exit....");
            Console.Read();
        
        }

        static void InsertRecord(string TimeFormat, string TimeToInsert)
        {
            Console.WriteLine("{0}: {1}", TimeFormat, TimeToInsert);
            using (OdbcConnection connection = new OdbcConnection("DSN=IRISHealth-WebDev; UID=; PWD =; "))
            {
                string insertSQL = "Insert into SQLUser.TestTimeData(TimeFormat, TimeTest) values('" + TimeFormat + "', '" + TimeToInsert + "');";
                // inserts a new row in the source table.
                OdbcCommand command = new OdbcCommand(insertSQL, connection);
                // Open the connection and execute the insert command.
                try
                {
                    connection.Open();
                    command.ExecuteNonQuery();
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }

            }

        }
    }
}