Drinking a bit too much beer makes me hungover yet I can drink enough wine to kill a horse and wake up feeling, at worst, mildly dehydrated

Possibly there is something about the beer that you're reacting to. Like, beer has gluten in it. If you have a sensitivity to gluten you get an inflammatory reaction, and a hangover is a inflammatory response too, so it might just feel like a worse hangover instead of a more obvious gastrointestinal sensitivity.