> I recommend hosting an e-mail server by yourself

As someone who did this from about 2001 until three years ago, I strongly suggest most people don't bother with this route.

GMail, Outlook, etc, all throw so many arbitrary and ever-changing security conditions to accept mail, it really isn't worth the hassle - or the lost clients from mails that don't reach their walled-garden end-points.

I've used Fastmail for a few years now, and I'm 99% sure that when I respond to an email sent from GMail, they'll actually receive it (So, I'm not talking about cold-emails, which I could just about begin to understand).