So endocrine is not that competitive; it looked like it was getting more competitive during the 2021 cycle when the match rate dropped to 75%, but this past 2022 cycle it jumped back up to 86% again (less people applied and slightly more spots), so it really depends on the year. But if you're a USMD without red flags, the vast majority match.
However, it definitely helps to have something on your CV that demonstrates your interest in endocrine, and research or case reports in the field do help to accomplish that. Especially if you're shooting for the top NYC academic programs research does matter, but to match at any program you don't need a lot. Kind of late to submit any case reports/abstracts this time of year, but if the poster presentation you did was endocrinology related that should help. At this point though as long as you apply broadly you should have a decent chance.
Your letters are important though, and although you should be good with having one endocrine letter, not sure about the utility of having letters from ID/Neuro. I was advised in the past that other than having letters from endocrinology, having letters from IM faculty are also ideal as they can comment on your skills as a resident. But if these other subspecialty faculty are able to do that as well then that's probably fine.