I see that in the docs recommend to use dedicated mail service and all of the blog that show how to set up the SMTP mail, they always use the dedicated mail service like mailgun.
According to This
" We strongly recommend using a dedicated email service. Email server setup and maintenance is very difficult even for experienced system administrators, and getting any part of the complex required email setup wrong means your email won’t be delivered, or worse, delivered erratically."
Where can I find these difficult step?
Is there any board or any that show how to do it?
I want to use my own SMTP server, but totally new with this.