If you create a new iOS SwiftUI App based on the "Hello, world!" template and run it under Mac Catalyst "out-of-the-box" (i.e. no further change) you'll also see a couple of [UIFocus] Failed to update focus with context <UIFocusUpdateContext: xxx: previouslyFocusedItem=(null), nextFocusedItem=(null), focusHeading=None>. No additional info available. messages. From this I'd conclude that the message as such is not necessarily an indication of a problem in the app itself.

Also note that this appears to be a regression defect as the code above works on iOS 18.6 as expected. It seems that I've stumbled upon a similar situation with UIKit (see Change tint of back button in UINavigationItem on iOS 26).

I have tried to use the approach described in TN3106 but I was not able to change the appearance of the back button. I got the impression that UINavigationBarAppearance is primarily useful for changing text attributes but I could not see how to set the color of the back button chevron image.

Actually I have no code so far to style the navigation bar. I am looking for code to put into viewDidLoad() to style the back button so that it has the same blue color as the other buttons. In my original post I have listed some unsuccessful attempts.

I would do so if I would see any chance that anybody would look at it or even fix it. Since my experience is that bug reports are basically ignored I am not in a position to spend any more time on this. Actually a similar case has been reported in NavigationStack back button ignores tint when presented in sheet.