The best solo business sits at the intersection of three things: what you are good at, what people want, and what you can stand doing every day for a year. Miss any one and you are in trouble. Skill without demand does not pay. Demand without interest burns you out.
The mistake here is starting from the product. Do not begin with a thing you want to sell. Begin with an audience or a problem. The strongest ideas solve a real problem for people you understand. If you already have a following, even a small one, you are holding a massive head start.