I like dancing a lot and am pretty good at it. My autistic dad is surprisingly excellent dancer.
Most people I see in clubs are awkward dancers who are like 'wanna dance, not sure how to dance, wanna look good so not gonna really let loose' dancers. Weddings have fewer people like that for whatever reason, least the ones I've been to, but that could just be a personal family thing. Smaller clubs that are on more on the fringe (local bands or not top 40 hits, places where there's no dress code for sure) will have more varied people who are more likely to dance all in more different ways.
I would think that if you're just a clumsy person with poor sense of where you are, that unstructured dancing would actually be easier to do and be good at. But of course that has potential to be more embarrassing.
Structured dancing is better for the social anxiety about not doing it right, because as long as you're at least making the right steps, you're doing exactly what everyone else is doing. BUT it's also much harder, I think, to become good at, if only because there is actually a standard to measure up to.
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Not autistic, I think
Prone to depression
Have celiac disease
Poor motivation