I work at a small company and one of my many hats is “the only IT guy”. I promise you, you don’t want to self host email. You will always be in spam filter hell and you’ll never really know if the email you sent actually made it to the destination until it’s too late.

Buy a domain, pay for an email provider, and hook them up. If you ever get upset with your email provider, find a new one and switch out the connections. That way, your email address never changes but where it’s stored can be.