I think her critique had to deal with automation happening before workers were in control, and that was the point afaik as then the revolution would not be organizable, and that it fundamentally bound workers to labor in a non libratory way but haven't read it in a long time. I think she does misread Marx in that a lot of her criticism seems to be thinking that Marx bounds human beings to labor, but imo Marx still wants people to escape the chains of labor on human freedom so the critique doesn't add up. She also thinks he's determinist which is a bad reading. Marx to me is fundamentally a radicalization of republican freedom, so her searches for how little tidbits of Marx hint at totalitarianism are basically illogically working backwards, in that she's presuming they exist because the USSR so widely misused Marx thus it has to be the kernels are there in his work.

Also note on her totalitarianism, the first draft of the work only was about Nazi Germany, there was no mention of the USSR at all. Why she tacked on the analysis of Stalinism at the end is unclear. Regardless her Totalitarianism is basically an update to the critique of Bonapartism.