Struggled with this for years. Had one unsuccessful attempt. From what i can observe, most people who try product development, have no idea what they are doing.
Because we are now not on the Upwork and not under their observation i think i can safely say that not a single of my 150+ clients over 15+ years who developed something from scratch, succeeded: it was all on the level "got things done, put them online, and then... nothing". Two had SOME sales but only one of them broke even and the profit was laughable and haven't paid for his own time working on it (plus the product itself ended up being sold in a very cynical way mostly to old people who had no idea what they were buying, i felt disgusted once i found out). So i know for sure that i shouldn't talk to my own past of current clients about it: they are clearly the wrong demography.
How else do i find out?
PS: i don't mean to say that all my clients' cases were failures. There were plenty of things ordered by employees/managers of already successful companies for who we did good work and it contributed to their business success a great lot. It's just that no one who tried to start from scratch, succeeded.