How can you deliver checkmate with a king?

Um... The red king is in checkmate/check before the white king could move, so that scenario is impossible

Delivering a checkmate with solely a king is theoretically not possible under widespread rules, as a king on his own cannot supply a checkmate to an opponent's king. However, there are eventualities in chess compositions or puzzles where a participant may also be required to checkmate with a lone king due to particular stipulations or rule modifications. These eventualities frequently contain the opponent's king being in a tremendously limited role or under unique constraints, permitting the lone king to supply a checkmate.

This is an excellent example of ChatGPT talking nonsense.