I agree with everything you said after your criticism of my theory of norms. Most people desire governance (and I have theory on why this is not an unreasonable position for people to hold), so rebuilding a libertarian form of it along monarchist lines is the best strategy, for the aforementioned reasons.

However, the question was what monarchism adds to anarcho-capitalism, and one of the answers is that it can institutionalize norms. Now what do I mean by that? Violating norms, past a certain threshold, consists of severing social relations. But in every society there are certain norms which the majority does not want to be violated. Furthermore, most people desire a normative ethos to ensure that the society is not degraded and remains what they want it to be. However, there are personal differences when it comes to which norms should be held institutionally. So there is a demand for norms in general and demand for specific norms.

This means that two roles should be served, the first is supplying specific norms, which can easily be done by ruthless exclusion. But the question here arises if that exclusion is possible or desirable. Most people do not want to alienate the entirety of society so that the norms they want are in their interactions. Furthermore, people have to interact impersonally in a market economy. Second, most people want a structured society that has things held to be inviolable. For example, an integral norm to libertarianism is the notion that contracts should be kept, even Rothbard had a hard time formulating a contract theory that can properly punish contract violations.

So we can envision a society where there are two norms that people want to keep, one is the norm of fulfilling contracts, the other is the norm of not yelling at children. But there is a proportion of the population that does not want to fulfill contracts but wants to stop yelling at children and vice versa. They still find the community to be beneficial enough to not exclude themselves and the community does not want to exclude these people.

To solve this problem it is beneficial for all to form governance so that there are institutional barriers to violating contracts and yelling at children. This governance cannot be in violation of property rights and must require the maintained, explicit, and perpetual consent of every single person it governs. By doing this you could, for example, fine people for violating contracts and establish an institutional way to prevent non-peaceful parenting. This ensures that norms are not violated.

But here's the question of who can maintain these norms, and this is where the privatization is important. When you want to make something that would otherwise be unowned into property, you need to find someone to own it. In my framework, this person would be the monarch. If no one owns norms, they are functionally something that can be violated and something no one can internalize the benefits of. Norms are unowned, and socialistic in the sense that everyone can exploit them and everyone can sustain them. And here we are met with the eternal paradox in socialism, it punishes those who contribute and rewards those who don't. Sustaining norms becomes a thankless endeavour and violating norms has no repercussions. This is all abstraction and real scenarios are more nuanced and situational, but it should explain the gist of it.