Start with a Website, Not a Mobile App
Given the fact that most people are already maxed out on apps on their device with just things like facebook and youtube, you're going to be hard pressed to get people to install your app just to try it out. With a progressive web app if they like your app they can add it to their device home screen without installing via the app store and without using up space on their device. Also don't need to pay Apple $100 a year but you have the same benefits as a native app. Now with wasm you can even include native performance from a progressive web app.