I know this will sound patronising, but have you read Engels ‘Socialism: Scientific and Utopian’ and Lenin’s ‘State and Revolution’. If not, these would basically answer your implicit question as to why we can’t just wish a perfect society into existence.

“Authoritarian”, like so many other liberal concepts, is an idea that - while not completely without reality - is designed to obfuscate how power really operates. For example, non-authoritarian states have freedom of the press. But that press is owned by and will only give the point of view of the Bourgeoisie. The point of Communism is to put power into the hands of the proletariat rather than the parasitic Bourgeois.