Keep trying. After cutting almost all sugar out of my diet I can enjoy cocoa powder in a drink with almost no sweeteners at all. The sense of taste seems to adjust over time as your sensitivity to sweetness comes back.
Isn't that something like the way the Aztecs drank it?
If you've had mole with cocoa in it, similar to that, but runnier.
I take cocoa powder (plus milk) with no sugar at all, because I drink tea with no sugar either. (And coffee isn't my thing.)
I used to drink commercial hot chocolate as a kid, but then went off it in favour of tea. When I tried it again several years later, I'd gotten so used to unsweetened tea that sweet hot chocolate was an instant no-no.
Making cocoa at home isn't an issue, but the odds of finding a restaurant or beverage shop that does it is rather slim.