Roasted coffee has variable amounts of acetaldehyde, but typically in the tens of ppm. So, coffee will present orders of magnitude lower acetaldehyde exposure than drinking even dilute alcoholic beverages.

I wonder more about soluble fiber carbohydrates leading to ethanol production in the gut.

Interesting. Well, I was not too invested in that theory, haha.

It also could be the ritual of the whole thing. I quit drinking, and got really into coffee drinks. Creating potions—the anticipation, the combination of fluids with different densities and colors, the foam that is produced by espresso when the pressure is just right—it is all kind of satisfying.