I'm going to give you the benefit of the doubt that you're being sincere, before I thought you were joking.
Three points. First, we would need to come sort of mutual understanding regarding the relationship between representative democracy and liberty so we know what we're comparing any other system to.
History seems to tell a very different story than yours regarding RD and liberty, even when ignoring that its failures have been ameliorated by technology. Keep in mind, your claim isn't even that RD merely reduces this risk but that it "minimizes" it, which is a very strong claim.
Secondly, in principle any system intentionally designed with the axioms of maximizing liberty, retaining stability, and hampering the government's ability to violate the first two axioms, especially with the luxury of modern technology, could conceivably reduce this risk more than RD.
Thirdly, with your flippant disregard of monarchy, it's pretty clear you're not familiar with neo-monarchist thinking over the last 20 years. Most neo-monarchists are chiefly concerned with liberty. The centralization of power and its risks and benefits, and further how to reduce those risks, is a major concern.
Lastly, functionally even traditional absolute monarchies did not entail power residing in solely in a monarch's hands. They governed with the consent of other aristocratic families and with the consent of the military. To be clear, I'm not advocating traditional absolute monarchy and nor are the vast majority of contemporary monarchists, I'm simply saying we have to be a lot more nuanced in our analysis of power.