We’ve had normal isekai where you turn into a hero, but this girl is from an isekai. Kishi Suzume is from the 18th century, summoned by a kingdom from another dimension as a hero of their lands. She felled their demon lord, and was set to live her new life as a hero of fame, only she couldn’t. Once summoned a spell was cast that linked her presence in this world to the demon lord, and once he died, she had to return, only now, its 2024, nearly 300 years after she vanished.

Reverse isekai on isekai-ception, been on my mind for a while now so I figured I’d swing at the concept. She doesn’t understand modern technology in any regard.