I think of the business model as the enabling “wrapper” around the “technical” solution you make happen. If you’re a plumber, it’s all the business stuff. If you’re a teacher, it might be the whole infrastructure of a school. In a non-profit, it’s the rest of the “onion” around the thing you want to do that actually makes a difference in the world.
A good (charitable) business model is scalable (in the sense of allowing you to reach the “right” size – not necessarily enormous size) and repeatable. It enables you to serve the people you seek to serve effectively and sustainably, ideally by making growth pay for itself.