I've got this idea that the worries in the first place are the result of learned automatic emotional responses that can be unlearned.

I share this idea. And I experience pretty significant insecurity and social anxiety (mingling makes me sweat bullets).

I wouldn't be so quick to dismiss the techniques mentioned as not the "something more" you are looking for.

If the model for cultivating the "learned automatic emotional responses" that leads to worry involved years of subconcious, negative, irrational self-talk (e.g. "everyone is looking at me and thinks I'm overdressed and has concluded I'm a social moron! Ah!'), then I think it is at least plausible that the reciprocal -- conscious, rational, postitive self-talk -- may improve the situation over time and with substantial practice. The reality is most people don't care to criticize us nearly as much as insecure people perceive they do... but it can take time to correct your perception once it has gone askew.

Is there a quick-fix/mind-hack? Maybe. Is it possible this is the sort of thing that requires patience and consistent effort to overcome? I think it is very possible.