I'm only 10 demos in this time around, and I've never had so many games that don't have a category yet. In those cases I leave category blank rather than use G&D 🤷‍♂️

It's okay to use G&D if the game does not have its own category. Lots of indie devs don't realize they need to add their game to IGDB. Using the general category is better than none at all. :)