Since updating to iOS 26, the system back button in my UINavigationController now has a rounded, translucent glass-like background (a “magnifying glass” capsule).

This breaks my app’s design, where I want a flat back button with only a chevron or icon and no background.

I configure the navigation bar globally:

let appearance = UINavigationBarAppearance()
appearance.configureWithOpaqueBackground()
appearance.backgroundColor = backgroundColor
appearance.shadowColor = .clear
appearance.titleTextAttributes = [.foregroundColor: UIColor.black]

UINavigationBar.appearance().standardAppearance = appearance
UINavigationBar.appearance().scrollEdgeAppearance = appearance
UIBarButtonItem.appearance().tintColor = .black