We must return this to the notion of gambling which involves betting in a game. So in general if a game is without betting then it cannot be said to be gambling in my opinion, because it goes back to the basic understanding of gambling itself. And I agree that gambling carries risks, and if there is nothing at stake then what risks will we get, because we don't bet anything and will not lose anything from that game.
However, if it is based on personal opinion, of course there will always be different opinions from one to another.
Didn't gambling start back then when money was not created yet and other things were paid when a gambler lost? Because I remembered when I was young, I was still in elementary school, when I was playing with my friends in the text card battle of marvels super heroes, when I won, I got a card instead of winning and when I accumulated a lot of cards, I sell cards to my opponents or teammates to make money for a small coin.
That is clearly different, the focus is when there are betting objects that can be categorized as gambling and what you do with the games you did when you were small is clearly the betting is about cards, not where the losers have to give to the winners?
There is a media that is a hero card there that is at stake which allows you to get an advantage when you win and have to lose if you lose.
That is clearly different from what the OP said because indeed in this case it is only about how we guess correctly and get profits but if we are wrong it doesn't have any impact.
Well for me, as long as you are taking risks and only relying on the whole outcome to the occurrence of luck and uncertainty. It is gambling. Money is just a tool. A great tool. like how we use to trade coins, assets, and properties. When you bet it without properly analyzing your edge and the outcome. When you don't have any control of the process but just bet one side over the other. It is gambling. You take risks with the hopes of greater returns. The more you bet, the greater accountability you must have.