Which is better, Criptext or Protonmail, a mail service that uses Signal Protocol?

I recently found an email provider called Criptext. https://criptext.com/. This is open source and end-to-end. And above all, it uses Signal technology. This saves the email content on your hard disk and not the cloud. Is this email secure? And which is better than Protonmail or Tutanota?

4 posts were merged into an existing topic: Which domain or country has the most privacy?