Several apps can graphically represent storage in detailed categories or by folders (or both). MacOS’s Storage view is quite limited and often shows large amounts of consumed storage that doesn’t match up with what a user thinks they’ve used. Especially on external drives, which the Storage display doesn’t break out into categories, or when System or Other seems to be occupying a truly enormous portion of your drive, and you can’t find a folder with that much data in it to examine.
MacOS can act in mysterious ways, and it can be difficult from either the Finder or through > About This Mac > Storage view to figure out exactly what is eating up your disk storage.