If you're using a third-party email client, but using a gmail email address, then PGP would stop Google from reading your emails (assuming the private keys aren't compromised).

If you're using their email client, then nothing stops them from decrypting your emails if they really wanted to. IIRC, gmail doesn't natively support PGP anyways though, so you'd have to use a third-party client.

Don't worry, your email to requests@luigifanclub.cc with the subject line of "next target" is safe. /s

The thing that stops google (or proton for that matter) is that you don’t give them the keys.

If you're connecting to gmail over pop/imap, no problem.

If you're using the native gmail webmail or google chrome... They could.

I don't think that googles mail Client supports pgp. And if you use a client you trust with Google mail, the content of your mail is encrypted.

They will still use metadata to track who you are talking to and about what. The Mail subject is metadata and therefore not encrypted.

So to keep your conversations private, dont use gmail, and probably don't use mail at all, use something build with encryption in mind.