[p0w3n3d]

My experience says quite the contrary: nowadays you have to be a mail giant to be able to send more than one mail. I.e. policy imposed by Gmail and M365 will keep you at bay from delivering the mail in more copies (e.g. to your subscribers), marking you as a potential spammer.

[Bender]

This may be just cargo culting on my part but when I warm up a new IP for sending mail I first email my mail server from Google, then reply to myself. I do this a few times and then they accept my emails without issue provided I am not emailing many people all at once before the IP has good reputation.

[e12e]

> will keep you at bay from delivering the mail in more copies (e.g. to your subscribers)

Well, sad fact is that one person's exiting subscription email is another person's spam.