Nearly all "new" frameworks have been Swift-only over the last few years. Like you mention, CryptoKit and widgets, but also Combine, the entirety of SwiftUI, an

Nearly all "new" frameworks have been Swift-only over the last few years. Like you mention, CryptoKit and widgets, but also Combine, the entirety of SwiftUI, and even smaller things like the ProximityReader framework they released with iOS 15.4. They're even rewriting Foundation using Swift while exposing an Obj-C compatible ABI. Of course, any new API in frameworks which are already Obj-C are usually written in Obj-C and exposed to Swift. This means new Obj-C code will be written for years to come.