“Double down” comes from blackjack—when you double your bet after seeing your...

https://dlf-ne.org/is-up-the-ante-a-gambling-term-unpacking-a-classic-business-idiom/

“Double down” comes from blackjack—when you double your bet after seeing your first two cards, hoping to win big. Learners often misuse it to mean just “try harder,” but it’s about risk, not effort