If you can push to 50-55 hours a week by e.g. working a few evenings a week, you may be able to make it work through a combination of contracting, outsourcing, and grit. (If you do not do a B2C startup. Those are harder!) There's no hard formula, but the basic idea is you can likely earn enough to survive through contracting for ~50% of the hours in a year. Relentlessly triage your MVP and launch quickly to paying customers. Then either reinvest the proceeds into labor in lower-cost countries to iterate on the product, or take a hit to your billable time to do so yourself.
If you get to $X,000 MRR, remember you can likely sell the business for a decent amount of money and start again from a more solid base.