[ThrustVectoring]

>the governments of those places will probably snoop your emails

Uhm, how? Gmail supports Transport Layer Security (TLS), and >80% of their emails to and from other providers do as well (https://www.google.com/transparencyreport/saferemail/). Reject non-TSL emails, give the server a public key and tell it to throw away the email plaintext, and the only remaining threat vectors seem like "get rubber hosed into disclosing your private key" and "server gets compromised, causing future emails (but not past ones) to get exfiltrated".

[stuckagain]

SMTP TLS doesn't and can't validate the certs. It is trivial to MITM it.