Comunism can only emerge from authoritarianism, by definition, because every single class society is authoritarian, and thus every state is. And as Engels noticed, revolution is the most authoritarian thing that is.
Imperialism is not the same as authoritarianism. To know what we mean by “imperialism” read Lenin’s “Imperialism: the highest stage of capitalism”.
And you might noticed how authoritarianism in my first sentence is used incredibly wide, it’s not a mistake, it’s one of those terms that have no useful meaning, it wasn’t even useful to start with, and especially not when it went through the liberal media and social media mill which had tendency to either purposefully or acidentally (or both) twist definitions to the point they are unrecognizable. Therefore to broadly talk about “authoritarianism” is meaningless, that word is unhelpful as definition and can be used at most as the cliche to deflect discussion (and note it’s been used in this thread in this characer extensively by liberals who sure as hell aren’t opposing it because they support authoritarian societies as well).