I use a lot of cocoa and 95% is Dutch process cocoa. I buy several brands because some are better for some things than others.
I am allergic to full-fat chocolate but have no problems with the Dutched cocoa and I think it is mainly because of the acids in the raw or "natural" cocoa or chocolate.
I can tell when drinks are made with "natural" or raw cocoa because I get almost immediate heartburn after drinking and it doesn't go away for some time, even with antacids and the same thing happens with cakes, etc.
King Arthur Flour company here in the US carries several different cocoas and my favorites are "Double Dutch" and "Black" - which is really almost black. I also use a lot of Valrhoma and Callebaut but also currently have Guittard and Frontier, which is certified organic and a Fair Trade item.
One of the smoothiest I have tried in recent years, but is not easy to find here, is Green & Blacks.
I just checked my pantry and I also have these:
Schokinag (red) Certified Kosher GMO free. It’s quite good but red is the predominate color and I prefer dark brown.
Bensdorp it’s okay but I like others better.
Cacao Barry Extra Dark (Extra Brute) (intense red color) the flavor is good but I like a darker color.
Black Onyx Cocoa Powder (Ultra-Dutched) should be mixed with standard Dutch-process cocoa powder for baking, otherwise result is a dry texture.
I don't have any on hand but regular Hersey's is a "natural" cocoa but their newer "Special Dark" is a Dutched cocoa and has become popular with a lot of cooks here both for baking and for drinking because they offered some great price breaks last fall, leading into the holiday season and the "big-box" discount member stores (Costco and Sam's Club) sell it in multi-packs at a significant discount.