She might, she might not.
Bear in mind that apart from Trump who made a big statement about NOT relying on the party machine to run government ALL presidents have relied on party apparatchiks.
Biden's presidential campaign is being run by Democrat 'movers and shakers' The selection of Harris is about widening the ticket, playing to the gallery NOT about talent or policies.
I doubt Harris has the talent to throw out the apparatchiks, especially as they are the ones who are responsible for her being the VP pick.
In the event Biden is elected as President then de facto Harris is the President in waiting when NOT if, in my opinion, Biden steps down through medical or mental incapacity.
IIRC Congress could elect a new president in the event of a president standing down, being forced to stand down. Some argue that is why Pelosi is promoting Amendment 25 proposals.