> Swift has come a long way and my guess is Apple has either embedded it into their platforms or added some fancy tree shaking for the binary. It went ABI around Swift 5 or so. I took a huge leap of faith, in 2014, and started using Swift, exclusively. It's turned out OK. I'm not quite as positive about SwiftUI, though. I think it will work out, but it has a huge amount of catching up to do, if it is to replace UIKit…
SwiftUI is pretty good, I've been using to build an app. The big problem is navigation and state handling, it's not intuitive (although I never used AppKit or UIKit so I can't say if it's better or worse)
I’m having a lot of fun with it at the moment. If you stay within the bounds of how they encourage you to build the apps, you can just go go go and with very little work release a fast, stable, native app across all their platforms.