I know I'm somewhere on this spectrum, but even at 35 years old I'm not 100% sure where I am on it.

I'm definitely asexual in the sense that the naked human form and/or genitalia do absolutely nothing for me. BIG pass on that. It's the aromantic part I'm still trying to figure out...because I'm not turned off by the idea of romanticism (with any gender), but I feel like I'm an android just trying to understand it. I don't desperately crave it, but I see others living their best lives with it and I wonder how that feeling would feel if I could feel it, like a colour blind person wondering what it would be like to fully appreciate a rainbow or a vibrant piece of art. Does that make me aromantic?

That does sound like aromantic! Id suggest looking into it more if you want to, including others experiences and different labels under the aromantic label!

I have watched dozens of videos about it from psychology channels, but while I seem to tick all the boxes, I also get a sense that most people who are truly aromatic are perfectly comfortable with being so. I'm definitely comfortable with being asexual, but maybe it's because of the fact that I'm also on the spectrum (many psychology videos point out there can be overlap between Autism and aro-ace), sometimes I feel like Data from Star Trek TNG; I'm genuinely curious what "love" feels like because I always see it get hyped up so much. This may be compounded by the fact that I have an EXTREMELY limited range of emotions (again, Autism), so most of the time I feel numb...or grumpy. I often remind friends and family that aside from "neutral" I really only have two moods; cynical ranting and "Heeheehee fuzzy plushie go EEEEEEE!"

There's one episode of Star Trek TNG that really kind of hits home what my flavour of romanticism feels like...or rather, the feeling of feeling I SHOULD be feeling something that I just...don't feel...making it almost...weird. To me, anyway. https://www.youtube.com/watch?v=sO_.....GHKiGM7w%3D%3D

There's a term under the aromantic umbrella, Cupioromantic, have you looked into that one?
But also there are people just in general who wish to experience it and such, and arent content being aro.

Hmm, I wouldn't say that I necessarily deeply desire to feel romance towards a specific person, more that I'm just curious what the feeling itself feels like. But this is also true for other emotions. Crying, for example. When I was a kid there were movies that brought me to tears just like they do for most people, but ever since I turned 18 I seemed to have lost the ability to cry, or feel any emotions that would result in crying. I've genuinely tried to force it by watching all those same movie scenes but...nothing. Again, it's why Data from Star Trek TNG is a good example of what my experience is like. Look up compilations of Data's quest to try and be more "human" to get an idea of what I mean.