I've been using Emacs continuously for three decades, 99.9999% of the time text-only (whether Linux console, X terminal console, xterm, or SSH client) on a remote server. My email client is VM, written in Emacs Lisp. I've used it to read mail for almost as long as I've used Emacs. VM (and ancillary tools, like Personality Crisis and mairix)

* does a great of job displaying HTML messages with Emacs's integrated W3M browser engine. For the very few that it doesn't, one keystroke sends the message to my web browser running locally.

* sends URLs I select (all from the keyboard) to the web browser (it doesn't use the add-number method; rather, W3M's built-in navigation keystrokes are available, including Tab and Shift-Tab for moving between links)

* opens images and attachments

* auto-adjusts the From: line of outgoing messages depending on the recipient

* archives messages to various folders using various criteria

* searches my archived mail at lightning speed

Of course, I can write Emacs Lisp code of my own to extend any or all of the above.

VM isn't perfect but, overall, I really feel like I have a superpower for email handling with it.