New privacy oriented email service provider (100% free and ad-free) - wiki?

I tried it out today and I’m impressed that my e-mail was relayed from my .onion e-mail account to various e-mail accounts on the clearnet and vice versa. That is, unlike mail2tor and torbox, who only relay to and from certain other e-mail providers you appear to have complete connectivity between your .onion site and any clearnet inbox.

I’ve been thinking about how to do that myself, on a longterm basis without being shut down by law enforcement, and I could only come up with methods that are unethical such as spam zombies. How does one have a public e-mail relay between Tor and clearnet without being harrassed by the state?