Make the first region and language you’re releasing your app into as big as possible. If you’re fluent in English, Chinese or Japanese, start there. Some app developers have made it after starting out locally but the bigger the market, the better your chances!
It’s often said that localizing an app in more languages should lead to some growth in download numbers but in my experience the impact was never extraordinary. It might depend on how much text is inside the app.
I would advise an incremental approach. Try with one or two languages to see how much impact it has on your numbers. Get a feel for the work it requires at your end whenever you update the app.
It’s also interesting to focus on countries where the non-localized version of the app is already gaining some traction to push it further.
Remember that some countries can provide you with many downloads without bringing in much revenue. Catering to them is still a good idea because more downloads equals more visibility for your app!