Mailtie helps you to forward your custom domain email into your mailbox and using Mailtie you would not be able to send emails. But here is the workaround for that: https://calderaforms.com/2019/05/smtp-gmail/
This guide will help you to whitelist your entire domain name: https://www.marottaonmoney.com/how-to-whitelist-an-entire-domain-in-gmail/
* In the "To" box type your domain name instead of the "From" box.
Absolutely yes, we also protect yourselves from spam and malicious emails.