The issues I usually notice is that people, my friends included, aren't always honest with themselves in how much effort they truly put in when it comes to engaging with others. That aside, sadly luck also plays a large part in getting noticed, no matter where we go.

There is nothing wrong with your work. You are also not alone in feeling that it's a upsetting to be online for so many years but struggle to build up a following that cares, I have friends in the same boat. -->

Genuine question: how often do you engage with other artists by following, commenting and reposting their art/etc? While it's true that OC art is less popular than well known characters, a big part of getting out there is engaging with the rest of the art community, making more friends & mutuals.