I only have experience with Proton. You must use their client or the web UI, or a "bridge" to standard IMAP. That's annoying. But I know it's private, and I ca

I only have experience with Proton. You must use their client or the web UI, or a "bridge" to standard IMAP. That's annoying. But I know it's private, and I can generate email aliases to use for each service I sign up for.