Fast and efficient way of sql operation ( INSERT/UPDATE ) an hierarchical

Question

Member class contains its services and types collection:

public record Member 
{
   public int id { get; set; }
   public string name { get; set; }
   public ICollection<Service>? Services { get; set; }
   public ICollection<Type>? Types { get; set; }
}

Calling stored procedure through Dapper:

public async Task<List<Member>> BulkSave(List<Member> items)
{
    var dt = ToDataTable(items);
    string sp = "SP_Member_BulkSave";

    using SqlConnection conn = new SqlConnection(_context.ConnectionString);
    using SqlCommand command = new SqlCommand(sp, conn);

    try
    {
        conn.Open();
        command.CommandType = CommandType.StoredProcedure;
        command.Parameters.AddWithValue("@tbl", dt);

        command.ExecuteNonQuery();
       
        return items;
    }
    catch (Exception ex)
    {
        throw ex;
    }
    finally
    {
        conn.Close();
    }
}

Insert/Update using MERGE statement in SQL and passing the List<Member> as DataTable to the stored procedure.

CREATE PROCEDURE [dbo].[SP_Member_BulkSave]
    @tbl udtMember READONLY
AS
BEGIN
    BEGIN TRANSACTION
    
    BEGIN TRY
        MERGE dbo.[Member] AS TARGET 
        USING @tbl source ON AND LOWER(source.name) = LOWER(TARGET.name) 

        WHEN NOT MATCHED BY TARGET 
            THEN 
                INSERT INTO (NAME) VALUES (source.name)
               
        WHEN MATCHED 
            THEN
                UPDATE 
                SET TARGET.name = source.name;

        COMMIT TRANSACTION;
    END TRY
    BEGIN CATCH
        IF @@TRANCOUNT > 0
            ROLLBACK TRANSACTION;
    END CATCH
END

This is working fine while inserting/updating the Member. but how to insert/update member's related services and types?