A software Engineer with 10+ years of experience here.

I would say that all depends on the idea itself and the technical complexity of the app.

If it is a pretty straight forward app you should probably hire a single developer/ team of 2 person to develop the app.

If the idea involves a lot of technical complexities it will be a good idea to get a technical partner first and then look for outside help. The technical partner will help you with some part of the code and managing the freelancer/team etc.

If you are not a technical person, you should really write down what exactly you need from the freelancer even before you start looking for one.

Do not go for the cheapest freelancer that you can find.