> totalitarianism is about control of the state over all aspects of the citizens' lives

The Roman Empire had no compunction about interfering in any aspect of citizens' lives. If it engaged in less interference in practice than many modern regimes, that was simply because there was far less for it to interfere with. Consider the education system – in modern times, education is near-universal, and so regimes seek to control the education system in order to influence the thoughts of the mass of the population. If the Roman Empire had universal schooling, it is near-certain that the imperial government would have done the very same. But, it didn't – the bulk of the population was illiterate and uneducated, while fee-paying private schools served the children of the affluent. The government never sought to regulate those schools, simply because it did not see any point in doing so. Why should the state care about the school curriculum when 95% of children never went to school, and the most of the 5% who did would have been children of regime insiders anyway?

Nazi Germany and the Soviet Union both subordinated all civil society organisations to state control. What did the Roman Empire do? Well, civil society – as understood today – largely didn't exist in ancient times. There were few formal civil society institutions, and those few which did exist were generally religious in character, attached to Temples/Churches/etc. And the Roman state heavily interfered with religious institutions – in the pre-Christian period, major Pagan temples were generally government-owned and with state-appointed clergy. If anything, the adoption of Christianity as a state religion saw a modest decline in government control of religion, simply because Christianity had an organised clergy not under direct state control, whereas the Pagan clergy were far less organised and hence far more amenable to direct state interference.

Fascist Italy was a different situation again – Mussolini sought to subordinate all civil society to the state just as the Nazis and Soviets had done, but was forced to compromise with the Catholic Church and permit it to retain its own independent Church-sponsored civil society organisations, which functioned as alternatives and competitors to the state-sponsored ones. Italian citizens had a freedom to choose between two competing ideologies (Fascism and Catholicism) – a relatively narrow freedom, but nonetheless one which was denied to those ruled by the Nazis or Soviets. The military was another area in which Mussolini failed to implement totalitarianism – Nazi soldiers swore allegiance to Hitler, Soviet soldiers swore allegiance to the Soviet State, but Italian soldiers swore allegiance, not to Mussolini, but rather to King Victor Emmanuel III. As a result, many royalist/monarchist opponents of Fascism found a refuge and power base within the Italian military – nothing parallel could be said about the Wehrmacht or Red Army.

Comparing Fascist Italy, Nazi Germany, and the Soviet Union, I think it can be argued that only the last was complete totalitarianism, whereas the former were less than fully "total". In the Soviet Union, the economic sphere was fully subordinated to the state; with private enterprise, private property and private wealth severely restricted (if not abolished entirely). By contrast, Fascist Italy and Nazi Germany allowed private enterprise and property to continue to exist, and both regimes permitted the wealthy to keep the bulk of their private wealth, provided they did not politically oppose the regime, and were not members of persecuted minorities. While both regimes did interfere with the operation of private businesses to a degree, they never sought the complete state control of business decision-making which existed in the Soviet Union.

> In totalitarian state people are typically oppressed based on the laws of the state driven by ideology, not because of the whims of the ruler. The whims of the ruler if happen, like in case of Stalin, come in addition to the totalitarian state oppression and don't change the nature of the state,

Why does it matter whether one's oppression is driven by "ideology" or "whim"? I can't see why this is an important distinction. And it seems rather orthogonal to the question of whether the state has "total" control over society. One regime might be highly ideological yet with significant spheres of society maintaining independence from state control; another regime might be founded on personal whim and the ruler's megalomania rather than any coherent ideology, and yet subject every aspect of life to those whims.

> and may naturally disappear with the death of the ruler while the totalitarian state would continue its existence.

Historically, many absolute monarchies have had no particular ideology, yet saw a succession of absolute rulers lasting centuries, as the role of absolute ruler is successively passed from father to son. The particularities of whim may change with each generation, but it is still whim; and sons likely inherit much of their whims from their fathers.

> Looking at pre-20th century history the closest to totalitarianism would be the Church's tight control over all aspects of the people lives in the Middle Ages

I think the mediaeval Catholic Church was actually far weaker than many people today think it was. It did not exert much control over the average person's life at all; many mediaeval clerics bemoaned that the majority of the population rarely went to church, and often acted quite disrespectfully on the occasions they did, indulged in widespread drunkenness, promiscuity, unmarried cohabitation, adultery, prostitution, etc, and that the government mostly didn't care. Even within the Catholic Church itself–very many "celibate" clergy had mistresses and illegitimate children (including bishops, cardinals, even Popes); homosexual activity was widespread in many monasteries (which while a capital offence, few were actually prosecuted–generally only the indiscreet, unlucky, or those who had made powerful enemies.) Many viewed religion as a fitting subject for mockery, and got away with it far more often than most today would think they did. Those who sought to establish a competing religious ideology to the Church's frequently faced execution, but those who decided to just ignore it all and quietly live their lives as they saw fit were largely free to do so.