“Double down” comes from blackjack, where you double your bet after seeing your...

https://milasultimatejournal.theglensecret.com/hedge-your-bets-finance-idiom-vs-everyday-use

“Double down” comes from blackjack, where you double your bet after seeing your first two cards, betting the hand will win big. Learners often think it means playing it safe—wrong. It’s actually about ramping up risk, committing fully