These days I use folders primarily for organizing tasks that must be tied to the filesystem, such as making backups, and for representing entire projects or super-categories. For anything more nuanced I just apply some of my 100+ or so tags.

e.g., if you collect “reaction” images, most images may show more than one emotion (angry, happy, sad, etc.), so you just lump them in one folder and tag each image with the relevant elements. Same for people and characters that may appear in more than one series, and images that will have more than one character, so instead of folders named after a series or character, you just have a “Movies” or “Anime” etc. folder and tag each image with the series’ name and the characters in it.