The fastest way to lose your money is to gamble on casino games. Particularly, RNG-based games. These include any games that rely on software to determine the outcome. For example, slots, roulette, blackjack, video poker, baccarat, sic bo, craps, etc.
These games come with a house edge programmed in them. Meaning even if you win, the house will eventually get their money back for as long as you are playing.
Sports betting is different. You can actually analyze a team's/player's performance and place your bet based on facts. I'll give you an example, Norway U19 and Norway leagues tend to have many goals scored. This applies to Holland, Spain and England U21, and Iceland leagues. I can bet you that these matches will hardly end without a goal. So, with a proper money management strategy, you can easily win more than you lose.
So, slots vs sports betting: SPORTS BETTING ANY DAY. If you want to profit from gambling, that is the best way to go. Also, avoid going for win-draw-win options. There are many options to pick from.