Security is not equal to privacy, but security is absolutely a means of protecting privacy. They asked how to protect privacy which absolutely is in the realm of security.

You don't gain additional privacy from using 2FA, but your personal info is less likely to be stolen versus person info protected by less secure authentication methods.

Privacy uses security to protect itself. Security doesn't increase privacy. It increases privacy protection, which is what they asked about.

Edit: shout out to proton mail though. It has some quirks that might turn off some people (mainly not being readily compatible with IMAP clients without the use of the Proton Bridge. But it's there for a reason and works. And honestly, most of the other stuff you said is pretty good too. The Microsoft/iPhone stuff is obviously arguable (I fall on your side of it) but in the end the best practices is to limit exposure. The less your data is accessible by others, the better. Using email masks (I use Firefox Relay) to minimize email leaks is another good idea.