playgrounds-uikit-app
This is a simplistic sample template for Swift Playgrounds 4 to begin with a UIKit-based app delegate & window scene instead of using SwiftUI as your entry point.
N.B.
Currently, when using a UIKit window scene, the App Preview sidebar in Playgrounds will not function correctly, and sometimes changes to the project may require closing & re-opening the project. Hoping there's a better solution for this in the future.