There are definitely speciality shops that sell dark roasts like you might want. One in the UK, Rave, sells the most amazing Italian-style blend with robusta mixed in. It's not fruity at all, just pure dark roasty flavour (yes, I've got an espresso bar lol.)

That darker style gets frowned upon a lot ("bleuch! it's bitter!"), as a lot of people in the space have kinda embraced the more fruit-forward lighter roast stuff (if you roast darker, you tend to obscure them.) I like that too (some stuff is kickass), I just categorize it separately from darker stuff.

I believe some people have started calling it goop, presumably as an anthesis to soup, which is very coarsely ground espresso typically using lighter roasts.

Not sure where you're based (US?), but there will be stuff out there. Try r/coffee or your local forum maybe? Once you find a really good one, you'll probably just stick with it :-)