For me it is social anxiety / being on edge around more than 4-5 people (apply from 1 person upwards if they are strangers) and having sensory overload because it is a bar / pub / whatever.
A lifetime of masking leaves its mark on a nervous system, i.e.
And alcohol down regulates / takes the edge off
You might look into neurodiversity / trauma in your life (if you haven't done so already)
What do you mean by masking? And can you elaborate on the neurodiversity part? This is the first time I hear about alcohol as something that's reached for specifically by neurodivergent people.
For people on the spectrum masking is basically roleplaying a "normal" person, by learning behavior that is associated with not being singled out as a weirdo.
This takes a lot of processing power and constant vigilance in order to not drop the mask which is quite exhausting.