I got a sample code as following that worked correctly on iOS 14 and iOS 15. But it seems to not work at iOS16, it there something missing on iOS16?
func showFontPicker(_ sender: Any) {
let fontConfig = UIFontPickerViewController.Configuration()
fontConfig.includeFaces = true
fontConfig.filteredLanguagesPredicate = UIFontPickerViewController.Configuration.filterPredicate(forFilteredLanguages: ["zh-Hant"])
let fontPicker = UIFontPickerViewController(configuration: fontConfig)
fontPicker.delegate = self
self.present(fontPicker, animated: true, completion: nil)
}