Turnkey mass mailing on my terms, where should I go?

Question

Mail server

In short, you need to make a newsletter from time to time, about 20 thousand letters. But I don't want to do it from the main domain of the site. It's better to make several spacer domains and send them from them. And so that when switching to a domain, a redirect to the main domain is obtained from the email address.
Does someone provide such turnkey services or will they have to deal with domains and emails on their own?

Answer 1

spammers, obviously
there are respected people on gray boards

Answer 2

Well, as an option, apply for a service to a mailing service, and they will find an agency or a freelancer who will do it. This is done, for example, by UniSender .