Assume you could be successful at serving any audience.
Who would it be and why?
What’s stopping you from working with them?
What research can you do to understand what they need so you can sell things to them to sustain a business?
My guess is you could succeed in serving almost any niche.
Don’t let your mind trick you into thinking one market or another can’t sustain a business. It’s rarely true.
You just need to figure out what you can offer them that they actually want at a price that works for everyone.