Have you checked out the Insights tool for this topic?
It looks like there is some very good, established competition in this topic. So although there is high student demand for it, it's also hard to break into it. As the tool says "bring your A game" to succeed in this topic.
Explore the top-earning courses it surfaces. Can you make a course that's so much better than them that students would buy yours, as a new, unproven course, instead? Could you perhaps complement these courses so that students might buy yours in addition to the existing top-sellers?
Anyhow, study the Insights tool - as a statistician, you'll know what to do with the information it gives you.