I won't be the most popular person on hacker news for this but check out bubble.io for the front end and then use heruku(free tier) + python(flask + fastapi, et

I won't be the most popular person on hacker news for this but check out bubble.io for the front end and then use heruku(free tier) + python(flask + fastapi, etc) for the API. With this stack you can quickly build a API, connect it to bubble and show people your idea in a way that's actually working. Later on you can move all your API data off bubble and replace the front end with whatever you want. I found it the cheapest and easiest way to build something very quickly.