I think it depends, 24 hours for a simple web based prototype? Sure, that is do-able. UI templates and graphics that don't require a designer or UX team cuts down on the process! I would say 2 weeks or less is really all you need for one good MVP as long as features and requirements are scoped right and the tools are known. I have done it the same way you are for full stack web applications, mobile applications with a backend, and desktop applications using Unity, Delphi, Python, and Vue. You have to have a mindset and tool layout as you would for a Topcoder competition, and you must know what cloud solution to use ahead of the sprint like Heroku, Firebase, AWS Amplify, or Azure (Heroku was the best, sadly they are removing their free tier, so now is just one of the better ones).