I pretty much ruled out Julia as good for Android (at least for now, while it CAN run there in some sense).
It’s because it’s easier to call a non-garbage collected language. I overlooked Swift is such as thing.
I do see outdated (and only worked on macOS): GitHub - JuliaInterop/ObjectiveC.jl: Objective-C embedded in Julia
People avoid Objective-C by now, but can you still do all iOS apps with it? Would it be helpful to resurrect that package?
Swift apps can be cross-platform to Android.
Kotlin apps can be cross-platform to iOS. What would be the preferred way? I would sure choose Kotlin, if only thinking of Android.