If our psychology were healthy we wouldn't need any of them, and none of them can help our psychology be healthy. They are altogether a hinderance to what we are, as human beings. They exist as fear based survival instincts, that perpetuate culture, which in turn perpetuates them, that keeps us all locked into a particular neurological holding pattern.
It's all rooted on the idea that without them we would be beasts. That we need rulers. Governance. A middleman to God, to our psychology. In truth, they are the reason why we have all the problems we do. None of them are the solution to our woes.
While I agree in principle with the sentiment, that firsf "
If" is doing a lot of heavy lifting. While I can easily see monarchies, clergy, nobility, dictators and whatever other similarly top-heavy forms of medieval totalitarianism as self-evident hindrances to human flourishing, and for that reason alone things to be rejected and consigned to the darker parts of human history, I'm not 100% sold on the idea that there
could never be a benevolent king, queen, religious institution or even a dictator in modern times who actually
did have a lasting positive impact on human psychology and culture.
It does seem that despite when comparing a monarchy to an institutionally (not compulsively) atheistic modern democracy, there's an easy winner when the objective is facilitating human flourishing, some form of centralised leadership has been and remains important for human progress, and I don't see human psychology getting healthier en-masse in the absence of that. Although of course you did say "ruler", not leader, which I recognise is an important distinction.
The main hindrance to a benevolent impact from an individual or group with absolute power as I see it is that in order to truly demonstrate benevolent principles in a way that might have a lasting impact on the society governed in this manner, the ruling individual, group, or class, would need to eventually voluntarily relinquish their absolute power, which although it might work in the context of a single generation, when we have dynasties and ancestral grievances between these dynasties and suchlike, will quite easily go badly. Ideally you'd need not just one benevolent monarch but a long line of them with similarly benevolent principles, such that when they do relinquish their absolute power, society is in a place where no one still alive is either pissed off about their grandma being burned as a witch or whatever, and the net psychological outlook is such that no one has an urge to immediately take advantage of the power vacuum and install themselves as another absolute ruler. And that kind of stretch of benevolent rulers over multiple generations is probably not within the realm of plausibility for human beings.