Social Democracy, as practiced in most Nordic countries, which are typically ranked the happiest countries on Earth, by surveys of citizens, year after year. Regardless of their wealth.
To the best we can estimate from extant hunter-gatherers, this is also the modern equivalent of our early tribes. Basically a cooperative with a high degree of sharing.
For example healthcare, in which everyone pays a fair share for the healthcare of everyone, which is free at the point of consumption.
Free, if minimal, housing if you need that; at least you won't be homeless or freezing or roasting.
Free education, through college, through a PhD if you want one. Free nutritious food. Free safety: like police and firemen, ambulances and emergency response, free clean water, free food inspections, free rescue in natural disasters, free courts, and so on.
The proof is in the pudding, the citizens are measurably happier with their lives, and more productive and successful in the bargain.
Of course that stuff is not actually free, it is supported by taxes, but the taxes are not that much higher for the typical person than in the USA, and in fact if we in the USA did not have to pay for our own health care insurance, unemployment insurance, and other expenses that are covered under Social Democracies, we'd pay more in taxes but have less necessary outgo, and have more spendable income!
That is because a government is the only entity that can truly run a zero-profit organization in which nobody is getting wealthy, and the people in charge are making normal civil servant salaries. The profits of the commercial insurance companies increase the net cost of the protections they provide, and inevitably leave out those that cannot afford them, and those people ultimately cost us all anyway, because of their bankruptcies and uses of services without paying for them, or incarcerating them for committing crimes out of desperation, etc.
Collectively providing necessities of life is the cheapest way to do it; that is proven by the countries that do it. And it is the most altruistic economic system extant today; it strives to minimize misery, and death, and poverty. Which is an achievable route to maximizing the happiness of citizens; addressing the common factors and stressors that cause unhappiness.
I should point out that in these systems there is no ceiling on how well people can do, they still have millionaires and billionaires. Just not at the expense of depriving others of their survival needs.