You connect your physical keyboard to an Android device and start pressing the tab key. And then shift tab. And sometimes - you circle around the UI but can not reach all interactive elements. Is this a WCAG 2.1.1 failure? Maybe it is, maybe you need to try harder...

Bogdan on A11y

Testing accessibility for native mobile applications can be challenging due to platform, version, and framework differences. A notable technique in Android, called 'Keyboard navigation cluster,' allows users to navigate through UI clusters using specific key combinations like Meta+Tab or Search+Tab. This method eases navigation of complex interfaces but is not widely known. Make sure to use these key combinations when checking accessibility to avoid unnecessary WCAG 2.1.1 Keyboard (Level A) failures.

Testing navigation with physical keyboard on Android hint – keyboard navigation cluster – Bogdan on Digital Accessibility (A11y)

Keyboard navigation cluster – trying to make keyboard navigation a bit simpler on Android devices