If this is your situation then go back to your 9-5 or change your field if you can - consider the full journey between where you are right now to this SaaS actually sustaining you in-lieu of a job or career. The time frame on that journey might be 6 or 12 months, or never. This is a lottery ticket at best and that's if you even ship a product.

The question to ask is, what are people still doing by hand? Then the trick would be to drill through the upper layers at which everyone has a different answer.