The message used to be "we don't keep IP logs" and now it's the opposite.
I'd be willing to bet 99% of services that say they don't log your IP, actually log your IP in some form. You're telling me all these companies just discard webserver logs? No chance.
[0] https://github.com/foxcpp/maddy
[1] https://github.com/LukeSmithxyz/emailwiz
[2] https://github.com/iredmail/iRedMail
Peer to peer services with encrypted communications are impossible to centrally control and monitor.
Regardless, they are not suitable replacements for email.