USBKeyboard.h cannot hold keys, use multiple modifiers or press multple keys at the same time.

Cannot send a keyboard commands such as CTRL+ALT+DEL.

Cannot hold down a key such as ALT then send TAB to open the switch application manager.

Cannot send a single modifier stroke such as the GUI/KEY_LOGO command.

Start with USBKeyboard.h and reproduce the reported cases: CTRL+ALT+DEL, holding ALT while sending TAB, and a GUI/KEY_LOGO modifier. Trace how key presses and releases are represented, then verify that modifiers can remain held while additional keys are sent and that simultaneous keys work.

Written by the indexing model from the issue text.