Money can buy happiness in indirect ways. It is the same kind of liberal fake dreams sold to people, like everything is equal (it is not). If everything is perceived as equal, why will anyone try to change anything? Everyone becomes lazy, comfortable, sedentary and anti-revolutionary.
Moderate amount of money and financial independence is essential for happiness and wellbeing. Income does not directly determine happiness, but it can provide access to resources and opportunities for social interaction.
Basically, if you have very little of something, any additional amount of it will increase your satisfaction by a lot, but only up to the point of satiation, after which happiness will not increase further regardless of how much more you have.
But a three year old can understand this. Give them one ice cream, they’ll be delighted, give them ten, and they’ll start throwing up.
Yeah, law of diminishing returns, or Pareto frontier, whatever we can call it. The "moderate" amount seems to be where capitalist elite leeches tend to try and focus on as far as salaries are concerned, so that people keep themselves busy in the rat race, outpacing each other like enemies. Expensive brand stuff mostly exists to give this perversion an ecosystem.