Bluetooth/USB Keyboard No Input Bug on iPadOS 26.1 (iPad Air M2 13”) – Vietnam Support Refusal

Bluetooth and USB-C keyboards connect successfully (shows ‘Connected’ in Settings > Bluetooth) but no typing input in any app (Notes, Safari, Settings). 3 different keyboards (Targus AKF003, Logitech K380, NuPhy Air75) all fail on iPad but work perfectly on Android tablet and MacBook Air M4 (macOS 26). Tried everything: forget/re-pair (all channels/modes), reset network/all settings, DFU restore, factory reset keyboards, off Full Keyboard Access/Vocal Shortcuts/Switch Control, wired USB-C test. Vietnam support blames keyboards (incompatible), but cross-device test proves it’s iPadOS bug