For private, end-to-end encryption email, you need to have both the sender and receiver use the same email provider, either TutaNota or Proton.

So for privacy, Naomi Brockwell likes TutaNota or Proton. But she notes that if you're sending email to a recipient who us using Gmail, well then your preference for privacy is futile.  For end-to-end encryption you need to have both the sender and receiver have the same email provider either to TutaNota or Proton.

But she warns, don't use Gmail, which most people use.  She cited Edward Snowden who said for meaningful communication, email is highly insecure.