Hillary also ran a shytty campaign and abandoned Michigan/Wisconsin assuming she'd win them, something no modern dem candidate has ever done. Kamala isn't perfect but not being a complete idiot is going to put her in contention.
The biggest challenge is gonna be the gender gap. White men are gonna vote heavy for Trump and ensure he wins the overall male vote (despite losing black/Hispanic/Asian men). Women in general are going to go to Kamala but the question is how bad will she lose the white woman vote? If she does worse than Biden or Hillary she probably loses the election. Biden got around 44% of white women, Clinton got around 43%. Do I think it's possible that white women outright reject Kamala because they don't want a black woman president before a white woman? Sure. But that would be more likely if she was running against a normal republican. Instead it's Trump so I expect Kamala to match Biden.
Other issue...turnout. I think turnout will be high no matter what, even if Biden was still on the ticket. But I expect it to be even higher now. And given that dem votes will be more reliably banked via early votes, I think Kamala has the edge in the states that matter. MI, WI, and PA all have democrat governors and secretaries of state. I really don't care what the polls are showing there....I think she wins all three because she can bank black, Hispanic, and young voters before election day and every vote will be counted. It's gonna be an avalanche of votes. Maybe Trump wins the election day vote by such a margin that he still wins one of those states (and thus wins the presidency) but I doubt it.