Monogamy is, if thinking in terms of game theory for quality of family life, the optimal solution for society: most players win with this model with minimal harm.
This is almost entirely correct. You said minimal harm. There is no harm.
However, if thinking in terms of nature, polygamy is better suited.
Polygamy is if our natural instincts are allowed to play out. The best genetics reproduce the most. So more and more children are born either beautiful, clever, athletic, or all of the above. Generations born of polygamy are more likely to be chosen as mates because they simply have better genes. I believe this is true even in the event that their upbringing was insufficient due to a lack of a father.
You are entirely wrong. In western countries there is a constant pollution of the minds of young people done by a select few, with the express goal to confuse their natural instincts and convince them that monogamy is bad, and polygamy is good. This has been going on in ever increasing doses at least since the 1950s.
The result is not people who are healthier, smarter or fitter. Quite the opposite, our health, intelligence and dexterity is decreasing and worsening at an ever accelerating rate.
The goal is to destroy western society, bring about the Great Replacement, and create a whole world of submissive slaves where nobody has the capacity or willingness to stand up to them. Then their power will be absolute, and when they decide they no longer need slaves, because machines have gotten to the point where they self design, assemble and repair, the slaves will be eliminated with no resistance possible.
Monogamy allows for more men to reproduce sure, but then the quality of human genes is lowered. This is made even worse by arranged marriages where even the worst genes are allowed to pass on.
In a polygamous context, the best males reproduce so that as generations go on, the genetic stock is improved. I do not know the limit to this, but it's easy to imagine the percentage of attractive, desirable people would greatly increase. So in a way, this is the better solution as more people are born as attractive, and able.
You're entirely missing the point. Under a civilized context, polygamy not only doesn't select the best genes, it in fact selects the worst genes. Genetics are not better off under polygamous debauchery, to the contrary, they are getting worse at an alarming rate, along with the rest of health. This is clearly not due to an excess in monogamy. The west has experienced an unparalleled destruction of the nuclear family unit, as planned. Once you destroy the family, the individual crumbles.
The polygamous male to female ratio of reproduction is at its worst (smallest) when there are few attractive men and many average or unattractive males caused by monogamy being forced for too long. The male to female ratio of reproduction is at its best (closest to 1:1) when more people in a society are attractive, healthy, with good genetics. So in perfect fashion, nature almost selects for monogamy if played out perfectly. To prevent genetics from deteriorating over generations, I believe a primarily raw diet is important as is the avoidance of unnatural medicine most notably vaccines which are especially potent at corrupting genetics.
Polygamy greatly favours the slave mentality, the slave diet which is veganism+insectivorism, and a total submission to harmful drugs, injections, radiation and other treatments sold as "medicine".
You keep missing the point, that in a monogamous culture, the traits that make a mate more attractive, are completely different to the traits that make a mate attractive under a polygamous culture.
You haven't addressed how you are going to deal with the 80%+ men who can't find a mate under your ideal polygamous culture. You can export them off to other countries, therefore exporting your problem onto others, and that's being done as well. Eventually the whole world will have this problem, and the only three possible solutions are:
1) Reversal of the decivilizing debauchery and a return to normalcy and monogamous nuclear family structures, as western civilized society has done for thousands of years and to great success. This must include mass deportations, as happened during the Crusades.
2) Mass castration of 80% of men, either forcible through surgery, covertly through injections, drugs and poisons, or via entertainment like videogames, sports and porn.
3) Massive wars where somewhere close to 80% of men are either severely injured or killed.
2) Is already underway. But it's unlikely to be enough when men start rebelling. You're probably going to have to choose 1) or 3). Even if 2) is enough, you should know that that's what you're really advocating.