>>2145575There's tons of unpopular trails on alltrails - as well as the community content section which is people self-listing their recordings of where they went on hikes which tends to have even more off-the-beaten-path stuff.
Trails tend to be popular according to how far they are from population centers, how easy it is to get to a view or a waterfall, things like that. Simply being on alltrails isn't that big a factor.
Also, I use alltrails to import .gpx files from elsewhere to create maps that easily display distance and elevation gain. It just has a good graphical user interface and is a modern-looking app, nobody is forcing you to take only the most crowded trails, but you can get a pretty good sense of which those are - anything with more than 100 reviews is gonna be more popular.