Swift and JS/TS are practically interchangeable compared to the high learning curve of actually using UIKit/Cocoa/CoreData/Xcode/etc and building applications with it.
I don't think language syntax is very consequential, especially Swift vs JS which really aren't all that far apart. What I yearn for when I build mobile clients is the ability to bring my own abstraction like I can on the web. Instead we're stuck with old-school overly-OOP abstractions on mobile without any truly compelling alternatives.
Like, the whole ViewController + delegation abstraction feels like using Backbone.js in 2020. SwiftUI is one step in the right direction, at least.
Javascript (and probably by extension Typescript) are too dynamic to really compile down to machine code while still retaining all features. The best you could do would be something Cythonish where every second line gets converted to a call to PyObject_blah. It's not clear that that would actually perform better than a modern JIT engine
In which case you've just invented a less portable way of doing electron type apps.
I love prototypal inheritance & JS' syntax.
I don't enjoy the swift I'm doing now nearly as much as JS/TS.