Hacker News Reader

You could setup a SMTP server and route your emails via Amazon/Asure/GCP. For less than 2-4$/m

That's not the goal of a local SMTP server though

And let them spy on my email? Why do you think I administrate my own server in the first place?

(I reckon being a paying customer may mean they do not collect data. I don't trust them not to, though.)