What mail provider best? Except for Protonmail and Tutanota, Disroot

I’m looking for a security and privacy-oriented email provider other than protonmail, tutanota, disroot. The necessary conditions are open source and end-to-end encryption. I gave a candidate to investigate. Please tell me if they are safe.
Mailpile

mailbox.org

Mailfence

NeutronMail

Criptext

FlowCrypt

CTemplar

ElectronMail

Cock.li

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