:( I wish it didn't take so long to get around to finishing the solution to the mail problem I've been working on for the past year. It's basically done except for the setup user interface.
But... this comment is in relation to the often recommended solutions that I think suck: And that is use Proton VPN / Proton Mail (more the Proton Mail, but ultimately Proton anything really, though maybe for a few other different reasons):
https://www.404media.co/proton-mail-helped-fbi-unmask-anonymous-stop-cop-city-protestor/