Unreal Engine royalties only start after you make $1 million from a project. Even then, it’s 5%, and waived for sales done on the Epic Store (whose 13% cut is almost a third of what Steam takes). If you are a small indie dev, you won’t be paying Epic a dime unless you start rolling in some serious dough, and even when you do, 5% of your revenue for using one of the most powerful 3D game engines is pretty fair