Given the chance of success in the startup space, I would take another route. If you currently have skills to get another job right away, do it. Then look for

Given the chance of success in the startup space, I would take another route. If you currently have skills to get another job right away, do it. Then look for a problem in the new job for which a solution is needed. One that really consumes a ton of people time. Something that would apply to more than just that company. Build that solution in your free time. If you already have an idea as it seems you do, try to find a related job in that industry so you can continue to build out the idea in your free time.