Belgian chocolate milk
Chocolate and cocoa powder are two different things

For drinks go with cocoa powder (Dutch process). Emulsifying the fat in chocolate is pointless and not particularly tasty. Chocolate is about 40% to 60% fat, cocoa powder is 10% to 20% fat

For the chocolate milk taste you generally want the milk fat favours, not the cocoa fat

If your cocoa powder is not bright enough, adding a little coffee will help, as will a little more roasting of the cocoa powder, but be careful, it burns quickly. I think many commercial chocolate milks use a little salt (Sodium or Ammonium) as a brightener**

In some countries you can buy "extra" or "premium dutch process" cocoa powder, it is very dark in colour, and has a lot more of that dark chocolate style flavour

**  The "that tastes nice and different" reaction