However you tends to define gambling, it would be incomplete if stakes, risks and challenging activities (competitions) are not mentioned.
You can defined it your way but my interest is to understand this>>> Are sports games or related competitive activities which stakes are involved between both sides or teams also gambling?
Remember, there would be a winner to be rewarded and a looser to lost the stakes.
Every activity that requires money and stakes are called gambling, no matter what type of game is that, if there's monetary value involved and risking any amount, then that's gambling. Even those sports betting activity, many people didn't recognize that as a gambling but for me, it is. In my own opinion, no matter which angle you look at it, you still spent money and took out money to bet. Even if we say that it's just a typical sports game, since you've used money and you're competing with the bet of the opposite group, isn't that considered gambling?