We human beings love to categorise and label everything. This important because each different label has slightly different meaning. The danger is that the same labels can be used, not to describe, but to disort, mislead and sometimes insult or abuse.

So we have under that heading, tyranny, dictatorship, despotism, absolutism, and your totalitarianism.

Assuming we want to describe rather than abuse. Totalitarianism therefore implies a kind of dictatorship when one previously political party has become institutionalised. A genuine political party ( as the word party implies, one party against others) can only exist really when others do. It’s a bit like gender, male and female are only genders because they both exist in contrast to one another. If there was only one gender then we could say quite logically there are no genders. Same with totalitarianism having a one party state is in fact a no party state. The institution calling itself a party like the CPSU or the Nazi Party were really state institutions which offered benefits to to those who deserved them for extra loyalty or service to the state.

This is different to previous systems only in the sense of trying to give the state tighter control over ideology. Absolute monarchy depended on the church to do this. Totalitarian states use the “ party” as the state’s ideological driving force to ( always unsuccessfully) control how everyone thinks. The Nazis were successful for a time in this since their state ideology on race had terrible consequences and justified conquest of “ lesser” peoples. Stalin’s super nationalist policies masquerading as “ communism “ ( no resemblance to anything written or uttered by Marx, Engels Lenin Trotsky Rosa Luxembourg or any of the great spectrum of socialist thinkers) were successful but the totalitarianism of the CPSU collapsed into the gangster capitalism that in reality it always was and now back to dictatorship.