https://theanarchistlibrary.org/library/jacques-ellul-propaganda

Here is a book on propaganda, check it out.

Edit: Also its funny that you talk about nuance, when you initially just dismissed the report saying that the KGB and CIA only produce propaganda, you clearly don’t know much about intelligence agencies, meanwhile when you were presented a nuanced argument you simply replied with

I don’t care

A more nuanced take might of been, I don’t think the document its self is propaganda, however the person posting the document might be a propagandist. Anyways there is no reason not to believe that the leadership of the USSR weren’t making decisions collectively, even if you think that Soviet Union was an authoritarian state.