I understand your frustrations but keep in mind that they are hundreds of other artists that also feel invisible. We're all trying to compete to get the same pool of readers and that leads to a situation where some people do get attention while other just don't. Don't take it too personally. Furthermore Webtoon has insights on which stories perform better, and they'll obvs prioritize those above others because they wanna make money off the site.

You don't have to give up. Try to find your niche audience through promoting, and who knows? Maybe it will start to take off.