Ultimately, prototyping is to communicate your ideas into something your team, stakeholders, clients, engineers to understand visually.

So whatever tool or tools to get the job done is a matter of your preference.

Personally, I believe keynote is great at the storytelling and communicating the user journey of the user experience. Whereas, QC or FramerJS gives you the power of getting the details of the interaction to be exactly the way it is intended.

One thing great about QC and building mobile apps for iOS is that you can speak to engineers language as you work closely from prototype to actual coding. For example, tension/friction In a bouncy animation can be tuned to the exact number the way designers wants it, and engineers just have to apply the spec.

The only thing I worry about JS is that the expectation of an mobile app is about performance. And running anything complex in animation that is build off of JavaScript always feels off in the performance and actual intended interaction. But it's probably more of my problem, because I'm not good with JavaScript.