“Double down” comes from blackjack: you double your bet when confident in your...
https://www.inter-bookmarks.win/double-down-comes-from-blackjack-where-you-double-your-bet-after-seeing-your-2
“Double down” comes from blackjack: you double your bet when confident in your hand, doubling risk and reward. Learners often think it means simply “try harder,” but it’s about upping the stakes, not just effort