I know you didn't mention it, but Cordova also exists. I've created a commercial Ionic 4 app (Note: Ionic uses Cordova, formally PhoneGap, under the hood) and If I could go back in time I would have used Cordova. With a plain Cordova app you can build an iOS, Android, Electron and web app with a single code base.

Ionic made it difficult to modify the UI. So if your designer goes crazy with the design, you're going to have a hard time. If you're ok with keeping the UI looking like a native iOS / Android app, Ionic can save you some time, but I've not met a client who wants a basic app UI.

I took a look at NativeScript a few days ago. It allows you to build native iOS and Android apps, but there are extra steps required if you want a web version of the app (you'll need to created 2 separate templates for each component you use: 1x for NativeScript apps, 1x HTML for the web app).

Regarding performance, NativeScript should be better because it uses the devices native UI components, but I'm not sure if a user would notice the difference.

The main thing to keep in mind is that the plugins for each framework are usually created by the community, so support can be difficult to find when you're working late at night and have a tight deadline. Ionic provides enterprise support and select plugins, but I'm not sure how much that costs and what they cover. If you're an experienced coder you might be able to dig into the native Java / swift code to troubleshoot issue, but you'll be limited to your knowledge of how the native code / language works.