I think that you have to do quite a bit more setup on email than most other services. There's SPF and DKIM and DMARC and so on. Plus spam filtering, setting up accounts and authentication, ...

Plus email is arguably more important than anything else, since it's kind of the lowest common denominator of the Internet; your dentist will probably send you an email to remind you of appointments, job offers will arrive via email, password resets arrive via email, and so on.

So it is a bit scary.

Having said that, as long as you're not hosting from a residential IP addresses it is definitely achievable. You can start with one domain and use it for low-value purposes (or for accounts that allow multiple email addresses, like GitHub).