Recommended app architecture

It depends on what your app does, how big your app is,... Anw, you can start with MVC and then try to migrate MVC to MVVM or VIPER. Good luck!

Don't bother too much about it at start, you will learn progressively.

MVC is the basic for a good code structure.
Once you master it (and notably protocols), you will find if using dependency injection helps make your code cleaner.
have a look here : https :// learnappmaking. com/dependency-injection-swift/

As for SwiftUI, it is being promoted. I still prefer UIKit, because SwiftUI mechanisms are not as flexible IMHO and not as mature as well.

So, start with Apple's tutorials (Intro to App development with Swift) for a good start.