Should I use SwiftUI or Swift?

So, to answer the question directly: yes should get busy learning SwiftUI because it is the future of app development on Apple’s platforms, but you still need to learn UIKit because those skills will be useful for years to come.

SwiftUI is a functional programming language that uses the View protocol to create reusable UI components.

So “SwiftUI” is the thing that draws buttons and stuff, Swift is the language it is written in , and probably the language that a programmer doing a “let’s show a list of flowers, let people tap on them, and see details about them” app uses.