The easiest way to have control of your email is probably to buy a domain name (such as example.com) and then use this on an account from an independent email provider.

If you're ever unhappy with a provider, you can switch to a different one without changing your email address because the domain still belongs to you.

There are lots of independent email providers, all of them let you use your own domain. For example @Tutanota, @fastmail and @protonmail are very popular.

#GrowYourOwn

@homegrown @Tutanota @fastmail @protonmail
But before you use Protonmail, be aware they won't let you use your preferred email client, but only what they offer you.
No IMAP. No Thunderbird, no K9Mail.
@kleines_z @homegrown @Tutanota @fastmail @protonmail a tiny correction: normal mail applications only through their (proprietary?) local proxy application.