Sometimes it pretends to be a game about stories, or adventures, but it isn’t. It’s a game about what you have- hit points, weapons, armor, spells, gold, and experience points. (It’s also about how good you are at getting those things.)
It mostly trades in two currencies- hit points, and spell points. (spell slots, metamagic points, whatever). There are others, but these are the most important. D&D asks you to risk those currencies in a dice game, with the stakes set in the fiction, modified by however good your character is at whatever you’re doing.
The rewards are always things you can write on your character sheet- experience points, gold, items. You don’t have to track anything else.
You can trade experience points for additional power and utility, allowing you to earn more experience points, which you always want.
You can trade gold for additional power and utility, but only to a point. It’s usually easy to buy all of the best items in the game, with additional gold being useless. The game doesn’t model economics, or any mercantile activity, or construction.
And that’s it. 95% of the game is either about getting resources or spending resources ( to try to get more resources). Everything else is window dressing or freeform roleplaying.