There are docs that specialize in sleep studies, it can be a neuro, a pulmonologist...look for a place that has a sleep study program. You have a lot going on. I assume you are an active healthy person, suddenly hit with perplexing symptoms, and it is disconcerting. Diagnosis can take years as the docs follow algorithims and sometimes hunches. I would be curious to see if there is something going on at night that is causing this....it is an easy test and might yield some info.

Skin biopsies are gold standard at this time for small fiber neuropathy. I recently read that muscle biopsies should also be done with that...but that is a much bigger deal, is surgical and I don't see docs jumping to that too quickly...quite invasive.

You are far from being idiopathic at this point.