He recommend Proton Mail. However there's been a few comments lately on hn that its privacy isn't really sufficient. I'm wondering what I can use instead? Self hosting seems not only burdensome but likely less secure.
Email is insecure. Protonmail is no less private than any other normal email host. Its convoluted e2ee setup may be more private.
You can selfhost just IMAP storage, and pay an email service provider to receive and store your mail for you, periodically archiving it to
your own long term storage and removing it from the provider.