State ownership is a product of Marxism - communism, it has nothing to do with the ownership of the ancient era, and not whether it is compatible with monarchy and with a monarchical system of any kind
Have you ever actually read Marx?
He refers to Aristotle, Plato, and other Greek classical writings in his own commentaries and letters about
Das Kapital and the Manifesto. Heck, Plato's
Republic is widely considered to be the first (known) description of a 'communist' society - as in, calling for common/state control of all property. Unlike Marx, Plato also foresaw that to achieve that would require a controlling group of leaders with absolute dictatorial powers.
Several Christian and the Zoroaastrian Mazdak movement in Persia all advocated 'common ownership and control' of all property. This was, in fact, one of the most common organizations of Christian monastic foundations throughout the period of the 7th to 16th centuries CE as well as 'splinter' Christian sects like the Hutterites, Anabaptists, and Waldensians.
Later, Thomas More's
Utopia described a society based on common ownership of all property - and Lenin after 1917 suggested that they raise a monument to More as a 'founder' of Communism!
Communist principles of state or common ownership and distribution of property were widely advocated during the Enlightenment (mid-18th century) by writers such as Rousseau and Morelly in France and was later picked up during the French Revolution as a potential political doctrine - reference the works of Babeuf, Restif, and Marechal.
In Marx's own lifetime, several social reform movements were based on communal ownership of all property, such as Robert Owen's
New Harmony community in Indiana, USA (1825 CE) or Charles Fourier's
Brook Farm (1841 CE)
So, by the time Marx and Engels produced the
Communist Manifesto in 1848 CE, they were trodding a very well-worn path of proposing State ownership/control of property of all kinds that had philosophical, political, economic, religious roots going back at least 2000 years. State Ownership was not a product of Marxism, nor were any of the doctrines identified as Communist in the 19th and 20th centuries: they were Consequences of numerous prior attempts at getting people to live that way, virtually all of which failed in actual practice, as did the modern Communist attempts in the end.