I would recommend you sports betting(because that's what I do), but if you are not into sports or anything about betting you can do online casino but I am warning you that some online casino can take a lot in your wallet because you might not want to stop because you are losing big, I also don't trust casinos that much because they are made to take more money rather than you taking more money plus there are chances that you will be a victim of casino rigging which is very frustrating because there was no competition done you were just swindled.
That's one of the reasons why I choose sports betting too, although I believe that sports can also be rig but at least its given and we have a chance to choose which side we think will win. As we gamble in sports in the long run, we will know a lot of things and we will mature and when we cap games, we don't only look at the stats but we also look at different sides action as games that are getting more public bets on one side could be rig.