SwiftUI is in an introduction phase and and sometime it is difficult to implement in a 100% SwiftUI app some basic functionality like to choice a contact from our contact list.
SwiftUI has solutions for placing UIKit views and view controllers inside SwiftUI views. Give a look to this tutorial from Apple, it will guide you to use UIViewControllerRepresentable .
Anyway this technique sometime can be tricky to use and it seems not working with some kind of view controller.
For these reason I have developed a very basic example for how to use the ContactPicker in a 100% SwiftUI application.
I have followed and copied the code written by the brilliant Artur Grigor that I have discovered in this Stackoverflow answer.
You can find my example here