Hello!
In the hope to find help here, I'm posting my question: How to customize back button's image?. I know that the short answer would be "use UIKit", but I think SwiftUI is fantastic and I want to stick with it. I tried with UIAppearance, but it doesn't work at all.
import SwiftUI
@main
struct MyApp: App {
		var body: some Scene {
				WindowGroup {
						...
				}
		}
		
		init() {
				...
				
				UINavigationBar.appearance().backIndicatorImage = UIImage(named: "arrow.left.circle")
				UINavigationBar.appearance().backIndicatorTransitionMaskImage = UIImage(named: "arrow.left.circle")
		}
}