I think breaking up the ISPs and media conglomerates would be much more impactful. I can't think of a single market segment where Google and Amazon lack effective competition. Facebook is already bleeding users, and how would you break up a social media company in an impactful way anyhow? Facebook's ventures outside of social media aren't even close to being monopolies.
Google would be fairly easy to break up among Alphabet subsidiaries, and Amazon could be split among Amazon.com, AWS, and Whole Foods.
She actually gets fairly specific about what she her plan is if you actually read the medium article linked in the first paragraph of the OP.