Not to rain on the parade, but in my experience, having had to email customers in bulk .. sending tickets and logistics requirements for large events .. I can tell you that self hosting this is a complete and utter waste of time.
You'll get blocked before the first batch of emails leave your mailer.
Not even paid MailChimp or Campaign Monitor could guarantee delivery.
The problem is not the platform for sending email, it's the centralised nature of email hosting, much of it is behind Google and Microsoft hosted services.
