It seems everyone will have different pain points, depending on their skills and aptitude for various aspects of the overall project. One person may be great with writing up app descriptions, making screenshots, and marketing, but struggle with actual development… while others will be just the opposite.

If I had to guess, it seems your main challenge right now is getting started, so you’ve created this post as a way to procrastinate, thinking if you do enough research, you can avoid any issues. The best way to go is to start. You’ll run into some issues, and when you do, you’ll be able to look for ways to solve those specific problems. Asking blanket questions like this will leave you worried about problems you may never personally experience.