Как убедиться в завершении асинхронных методов

public class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine("Starting the export");
        var configs = new XeroExport();
        configs.GetConfigs();
        Console.ReadLine();
    }
...
}
public async Task GetConfigs()
{
    ...
    con.Open();
    var Reader = cmd.ExecuteReader();
    int i = 1;
    ...        
    if (Reader.HasRows)
    {
        while (Reader.Read())
        {
        ...
            DBExport(reportDate, entityID, await Xero_Connect(clientId, clientSecret, entityID), tenantId);
            i += 1;
        }
    }
    Reader.Close();
    con.Close();
}
 
 
public async void DBExport(DateTime reportDate, int entityId, AccountingApi apiInstance, string xeroTenantId)
{
    ...
    await Call_BalanceSheet(reportDate, entityId, startDate, endDate, apiInstance, xeroTenantId, accessToken, connectDB, dataDB, tokenExpiry);
    await Call_P_and_Ls(reportDate, entityId, startDate, endDate, apiInstance, xeroTenantId, accessToken, connectDB, dataDB);
    await Call_Accounts(reportDate, entityId, apiInstance, xeroTenantId, accessToken, connectDB, dataDB);
    await Call_Organisation(reportDate, entityId, apiInstance, xeroTenantId, accessToken, connectDB, dataDB);
    await Call_TrialBalance(reportDate, entityId, startDate, endDate, false, apiInstance, xeroTenantId, accessToken, connectDB, dataDB);
    await Call_Journals(reportDate, entityId, startDate, endDate, false, apiInstance, xeroTenantId, accessToken, connectDB, dataDB);
    ...
}

public async Task DBExport(...)

List<Task> items= new List<Task>();
if (Reader.HasRows)
    {
        while (Reader.Read())
        {
        ...
            var item = DBExport(reportDate, entityID, await Xero_Connect(clientId, clientSecret, entityID), tenantId);
            items.Add(item);
            i += 1;
        }
       Task.WaitAll(items);
    }

configs.GetConfigs().GetAwaiter().GetResult();

public class Program
{
    static async Task Main(string[] args)
    {
        Console.WriteLine("Starting the export");
        var configs = new XeroExport();
        await configs.GetConfigs();
        Console.WriteLine("Export complete");
    }

Task.WaitAll(items.ToArray());

await DBExport(reportDate, entityID, await Xero_Connect(clientId, clientSecret, entityID), tenantId);

public async Task DBExport