I'm a bit confused by this take so my apologies if I'm missing the point. SwiftUI leans far more in the direction of declarative layouts with very little actual code required. It defaults to bottom up sizing so that view sizes are based on their contents and automatically uses default system spacing for basic layout tasks.

The only comparable thing in UIKit is UIStackView. In fact, UIStackView was clearly added to reduce the explicit constraint layout code required for simple layouts. While you don't "write" UI code with Storyboards, it's certainly there, just encoded into a non human readable format.

SwiftUI has many problems (mainly bugginess and missing APIs) but I don't see how the old APIs required "not much UI code ... to be written". If anything, this is one of the primary benefits of SwiftUI: getting to remove most of the explicit layout code and complex type system required to do basic layout tasks with UIKit or AppKit.