Self-custody your email!

https://hub.docker.com/r/mailserver/docker-mailserver#!

Its a bit of a nuisance setting it all up, and you need some kind of domain name.

But do it once and put a Tor hidden service in front of it for access and you've got your own Protonmail. TLS is enabled by default, too.

If you need to hide your IP, don't do this, you need a hosted service and your ability to protect the contents of your email against snooping is minimal then.