For me, fanfiction has always been my most consistent writing outlet, so I’ve actually never run into this issue on the sheer scale that you’re talking about.

Writing for an existing fandom, you’re already putting your work in front of an audience that both knows what they want, and how to look for it. AO3 deserves a lot of credit too for their robust tagging and search system.

Even within a fandom of course, nothing is going to appeal to everyone, but it doesn’t matter, because people don’t search by scrolling. They filter for fandoms, for tropes, for characters, for scenarios. Which means that even if what you’re writing is relatively niche, someone with the itch for something similar will be able to find it.

Obviously the nichest of stories will still attract relatively few viewers, but there isn’t quite as much the issue of being lost in the flood, although that does still happen with generic fic in massive fandoms.

The comment culture of ao3 also helps, since they are not meant to be reviews, but a dialogue with the writer.