The Roman Empire, for example, would have a base tax rate of about 10%, and on a bad day, it can go up to 30%. Here in America, the income tax alone will take 30% of your earnings before the IRS even comes in to collect their share. Not to mention that even liberal "democracies" had laws up the ass restricting speech and gun ownership, and after 9/11, (some would say even before) our security and intelligence apparatus and their deeds would put even the Oprichniki to shame.
I mean, where else can an intelligence organization like the CIA get away with spiking CITIZENS OF THE COUNTRY with LSD? (
https://www.npr.org/2019/09/09/7589...d-control-torture-lsd-and-a-poisoner-in-chief /
https://www.history.com/news/did-the-cia-secretly-dose-people-with-lsd ) If a monarch tried to do that, not only would his peasants revolt, but his lords would denounce him, and maybe even other royal family members would be leading the charge against him. In a modern-day republic where people just take it as an accepted truth that democracy = freedom, they sure as hell can get away with using citizens as guinea pigs for their crazy experiments. Or doing stupid shit like sending guns to drug gangs (Operation Fast and Furious) or financing terrorists (Operation Cyclone).
Sure, monarchies have invaded other countries for taxation, slavery, and exploitation, and in the case of some, they've even eradicated entire tribes now and then, (like Spain with the Aztecs/Incas) but that can hardly get close the crimes done at the hands of so-called democracies, such as slavery, (which existed in America up to 1860) eradication of entire tribes, (which kept on going up until the 20th century) and forced sterilization (which continued up until the end of WW2). Democracies are no better than monarchies, hence why the Founding Fathers wanted a very limited government, with them being very aware that a democracy can be just as oppressive as a one-man dictatorship. And of course, Communist China did start off as a sort of "republic" in that they won the support of local farmers and the populace, and gained their support against the Guomindang, before they went full mad tyrant and began eradicating entire segments of the populace for defying them.
This is what I was talking about when it comes to virtues and vices of monarchies and democracies. With monarchs, the worst thing they've done is push down on peasants to pay taxes or go brigand and attack other nations for lebensraum and resources. As much as the average American would like to imagine medieval life as Game of Thrones, in actuality, many Medievalists can tell you that such a portrayal is hardly accurate. If you want a clearer picture of what went on in those Medieval days, go read up Regine Pernoud's books on the Medieval Era, such as "The Crusaders" and "Those Terrible Middle Ages!" The era of monarchs is hardly as bad as the democracy-lovers tend to portray it to be.
To put it in modern terms, having a monarch was more like having a president for life who still has to ass-kiss enough people to gain their support, because they're afraid that if they lose the support of enough bishops, lords, and towns/cities, they could get overthrown by their dissatisfied subjects who could just as easily crown someone else in their stead. Especially since having standardized national armies were a modern innovation, for eons the kings relied on whatever bannermen who supported them and whatever mercenaries they could hire, and those guys could just as easily join the opposite team and support usurpers instead. Both Western European monarchs and Asian monarchs have been overthrown now and then, with Byzantium having at least 30 Emperors get overthrown violently while some Chinese dynasties ended with them losing the Mandate of Heaven and the people's support.