"Double down" comes straight from blackjack—when you’re confident, you double...

https://idiominsider.com/talking-odds-at-work-the-risk-idioms-every-english-learner-gets-slightly-wrong/

"Double down" comes straight from blackjack—when you’re confident, you double your bet for one more card. It’s about committing fully, not just hesitating halfway. Learners often confuse it with “backing down,” which means quitting