The breakthrough came from the forum's collective brainpower. Users discovered that and recent X-DIAG updates were specifically re-engineered to be compatible with the newer OS architecture.
If the Launch update agent is not disabled, it may attempt to force an update that overwrites the user's modifications. The agent must be frozen using ADB commands: adb shell pm disable-user com.launch.update . X-DIAG - X431 - DIAGZONE - Android 14 - MHH AUTO - Page 1