I'd start even simpler and use a tool like Figma to prototype the UI and workflows that are at the core of your app. Then start actual development based on the

I'd start even simpler and use a tool like Figma to prototype the UI and workflows that are at the core of your app. Then start actual development based on the feedback from showing it to potential users. A lot will depend on why you need cross-platform support at launch. For most direct to consumer apps, your intended user base should skew to one platform or the other and should be large enough to support a beta and launch on a single platform. Not launching with both platforms supported won't make or break your app and launching with both without much mobile experience to begin with could even prove to be a distraction while you try to iterate on you're app's design. If you're selling an app to businesses, then not supporting both iOS and Android at launch would be a real roadblock. In that case starting and maybe even staying with Ionic could make sense.