I would say constitutional monarchy has done better than republicanism for those failure modes.

Economically, light socialism has also done better? Eg. Sweden or Canada.

Constitutional monarchies, specially the more successful ones, are in practice mostly indistinguishable from a republic. The powerless diplomatic figure that is the monarch does not impact the overall decision making in any meaningful way.

Sweden and Canada fit that definition as well, and are not socialist countries according to what Marx meant by socialism. They're very much countries with a foundation of ownership rights and private enterprise, but taxed to a certain extent as to fund extensive government welfare programs. Of course, I'm not unaware that socialism is a word used loosely these days but within the context of discussing communism it's important to drive home the difference.

And of course, as someone that doesn't belong to any of the mentioned countries, I would say that the sentiment that a government like Sweden's or Canada's is better to live in than (pardon if I'm reaching here) the country that I believe you had in mind when making the comparison, is not only not universally accepted but very heavily debated across the world.

Constitutional monarchies tend to have a symbolic figurehead for the public to emotionally invest themselves in, but who is restrained from exploiting that public affection for political gain. I think this is valuable.

If the Netflix series "The Crown" is to believed, this is not quite true.

It is a major difference though, since they could do something if there's some large issue.

In a republic, the person with that power is also the person usually making the decisions, so when those decisions are bad, there isn't another party with the power to stop them.

In Canada at least(Canadian here) the Governor general does step in at times to prorogue or dismiss the government.

Socialism lost all proper meaning in the McCarthy era, but Canada and Sweden are specifically not capitalism in the way that capitalists say free markets are always better. The US is more capitalists than both those countries, and is worse off for it.

Certainly if you consider it hotly debated, you can't say that capitalist republicanism is the least bad, since alternatives are equivalent

I think Capitalism is the failure of society. Where I live, I have to pay someone to be able to sleep inside, to eat, to travel, to communicate, to access information. And the only way to make those payments is to obey one person or another who gets power that trickled down from the top. Socialism is nothing but the attempt to fix these things by organizing like minded good people to be social. It might not always work, and nothing can last forever, but to the extent it does, I think that is the measure of good over evil in society. A capitalist republic is the organization of like minded authoritarians who maintain a class of people like me to use as labor and manage via economics and trade. As I see it socialism is the only sincere attempt at a fair society and republican capitalism is just authoritarianism with a delegation-style of management. IE: federal bank pays a corporation that bids on a job. corporation pays producers. producers pay servants. and on down the pyramid. And all the way down, there is no accountability to any good or fairness. In fact, the opposite is protected, because the way that an authority wants to treat their subordinates is considered human rights in capitalism. they call it privacy. corruption is the system. Pursuit of happiness (a euphemism for greed) is good. I think fair access to natural resources without needing permission is human rights. I believe that is called socialism. I don't demand service or subordination from anyone, just fairness, by which i mean equal or at least a minimum basic access to land or material resources to live. Capitalists demand service from me and respect for their perspective that i don't own resources and they do since they have exploited and conquered more people than I have, which they call fairness. The state = The status. It doesn't disappear people. Capitalism and crime disappear people. This just means the state is poor/capitalist. An elected body is not the state. It is just an organizing scheme for people to communicate and participate in the kind of economy where 1 person = 1 vote and no one is allowed to gain more or less influence than that except by true social means aka popularity. Your argument reminds me of people arguing against the scientific method because most or all scientists make mistakes. It just means you need better science. Science isn't a guarantee, but it is an ideal method of determining objective truth. Capitalism is the false utopia, with invisible hand and other superstitions. Socialism makes no such promise. It doesn't promise equality of outcomes. It is just a method for fairness. It is democracy that has not been corrupted by respect for unaccountable accumulation of private control or power.