Great list of suggestions. One thing I would add to your list that is super easy to start doing right away is to switch your email message viewing to text-only instead of HTML by default with your email client. This will prevent tracking when viewing emails and also make phishing links easier to spot. Most of the time you can get what you need from an email with text-only viewing.

Sometimes you might have to view an email as HTML to be readable, but usually there should be an option to not load remote content when doing so in your email client.

Text-only email by default is a great privacy preserving step that is also easy to do.