I’ve used mutt for many years as my only email client because it’s fast, configurable, powerful, and, most important of all, not broken:

https://lwn.net/Articles/837960/

I don’t have any problem with HTML email. Mutt formats it inline using links (my current choice), and if I want to see the graphical version, I just hit `v` to open the attachment menu, hit the arrow to put the cursor on the HTML attachment, and hit RETURN to pop it open in my browser.