Speaking of interstitial cystitis, it was news to me that it can manifest as just needing to urinate more often, as opposed to a feeling that translates to pain.

Yeah, as far as I can see the boundary between what gets classed as IC/"painful bladder syndrome" and what get called "overactive bladder syndrome" is very fuzzy and imho useless; which label you get seems to be dependent on which consultant you see (and how up-to-date their knowledge is or isn't).

Also wow on signals switching on you, that's fascinating.