She doesn’t have to worry about people turned off by Biden in general to win the nomination. She doesn’t need to care about voters at all to win the nomination, she just has to appeal to a handful of DNC operatives because the primary is over.
Assuming the Biden can’t simply reassign his delegates to Harris that is - in which case she’s essentially already won the nomination before she even started running.
Now the election on the other hand…the election also isn’t particularly about what she has to offer. The election is all about Trump. People are either voting for Trump or not-Trump, and the vast majority of not-Trump voters aren’t all that concerned with what form not-Trump takes so long as it isn’t Trump. It’s entirely a matter of turnout.
I’m more curious whether she’ll go for a milquetoast generic moderate Democrat or a progressive well to her left - if nothing else it will say something about what she sees as her bigger weakness. I’d put odds on a white guy either way to appease the lesser racists (aka the same reason Biden was Obama’s VP).