How to organize a small mailing list on VDS?

Question

PHP

A question for experts who really understand. I have a lot of theories. On the web, such topics are very vaguely described or too complicated. To the point:
There are several internal projects that require promotional mailings. There are clients whose resources we support. They also need a mailing list, we would like to provide our customers with such services.
There is a dedicated server with ssh access (OS linux debian).
Question: how best to organize a mailing list for several (say 10) resources?
How to properly configure the server, what are the pitfalls?
What literature or articles can be read to better understand this topic?
In the future, I would like to scale up and develop this to the level of servicing not only the clients to whom we provide development services.
Sending with the mail() function is not considered.
If possible, please describe the SMTP sending process. How to do it right .

Answer 1

www.mailwizz.com Scales
easily. All settings can be googled.
Pitfalls - getting into spam.
www.soslan.ru/tcp/tcp28.html

Answer 2

https://support.google.com/a/answer/81126?hl=ru start here.
Well, how to configure Exim in accordance with these recommendations - half of the Internet is used up.