I think any of her previous positions/votes count for relatively little today. They might count for folks who would never have voted for her, but that doesn't change anything. It might count for those who would vote for her every time, but that doesn't change anything.
As for those who MIGHT or MIGHT NOT vote for her, few will pay attention, I suspect, and be more influenced by the debates and what she says today. They spend billions, literally, on TV ads, the majority of which says the "other candidate" is horrible. Negativity sells, in a sense.
What we're hearing is "Trump = Hitler" and "Harris = Lenin".