I think it really depends on your category. I am kind of in the same boat trying to promote my app, and I did follow the advice of making a MVP and trying to get feedback before moving on. But even after doing that I am struggling to reach the right audience without a marketing budget
I also have heard that trying to sell something before making it can tell you if it has real demand. People will tell you something is a good idea and not use it themselves all day long, but they will not pay you even a discounted price for it if they will not use it most of the time. Here is a link to the podcast episode: https://www.youtube.com/watch?v=Ec9K6ZV3Ds4
