[f_devd]

EDIT: didn't realize this was satire when I wrote this

Setting it up from scratch is extremely annoying but there are foss solutions which manages everything mentioned and more, you only need to install & add the specified DNS records. Modoboa does a great job at this: https://modoboa.org/en/

> Also apparently there's no real way to migrate between email servers either

This seems false (unless I'm misunderstanding), you can just setup a second mailserver, change DNS records and run IMAPsync to get everything transfered (backend-indepently), the only thing that would need additional consideration is passwords.