Which of the gambling game do you think that is the fastest in bringing profit base on little time duration
Crash, roulette, dice and slots. You can win instant profit BUT that is if you're lucky to win. Most gambling games are luck based hence you cant expect to win in these games if you're not lucky. If you're not prepared to lose then dont gamble, because the chances to win depends on the game that you'll play (since there's a chance based and skill based) and of course luck. So gamble with less expectation and in moderation.
Luck in the end is just maths. Most games give a lot of advantages to the casino in the long term. It's only a few games that have a more competitive chance, but in the end every single game gives advantage to the casino, so in the long term the gambler will end up losing money.
That's why casinos continue to exist.