We all know we can block calls and messages, but what about email? I get the same junk emails daily. Sending them to junk and trash doesn't block them. Is this something that can be done through the mail app?
Generally this kind of thing is best done server-side rather than on the client. What sort of an email provider are you using? Have you explored their spam/junk mail options that would usually be available in settings when you access your account through the web?