I think severity of hangovers is more due to genes rather than amount of alcohol consumed.
I stopped drinking mostly due to multi-day hangovers but people I know who drink MUCH more than I ever did experience mild or no hangovers. I get a mild hangover even if I only had a single beer. Caffeine doesn't effect me at all though.
As someone who hasn't stopped drinking, it very much matters what you drink too.
From the well known "sweet == hangover" to more subtle stuff like different brands of the same kind of drink having a slightly different composition that agrees more or less with your liver.
Of course, if you get drunk every day, the above subtleties cease to matter. And even if you're a weekend warrior, you've got to take breaks or water your wine* or put more tonic water in your tonics if you want to do an all nighter.
This is why I think it's mostly genetic - it doesn't for me. Literally any and all alcohol gives me a hangover. Drinking water doesn't help me avoid them either. I've drank SO MUCH water to try to avoid hangovers, they always happen no matter.
I stopped drinking mostly due to multi-day hangovers but people I know who drink MUCH more than I ever did experience mild or no hangovers. I get a mild hangover even if I only had a single beer. Caffeine doesn't effect me at all though.