We agree on one thing. She is an awful candidate. Probably the worst in history. However, there a couple of things you just don't seem to grasp. Unlike pubs, democrats will vote for whoever is on the ticket even if they don't like them. They are still going to vote "D".
The other thing is that many are voting against trump and not for harris.
Where trump was winning was primarily with some independents and minorities. Even some traditional suburban pub women voters likely came back that just stayed home in 2020 when he turned them off. If you followed the polls, for much of the year, neither trump or joe were polling above 45%. Even in the % voting for trump there were voters who were not "firm" or 100% committed to that vote. There was a significant % of undecided and not very firm votes. Shockingly, during the debate, trump actually listened to the people advising him and stuck to issues at eh same time joe was putting his dementia on full display. The result was many of those undecided voters moved into trumps column. Part of that was the media came out attacking, or at least questioning, his mental state which certainly moved the needle for some who still think the mainstream media is remotely trustworthy.
When trump decided to go away from the issues and start back with personal attacks, and making statements that offend women, minorities, and people in general, those previously undecided voters, as well as some former trump supporters(likely minorities) moved to the harris column. It's math, and not hard math. You probably have about 15-20% of voters MAX in every potus election that would even consider changing their vote based on who the candidate is. It's not like it takes 20% of the people changing their mind to make a massive difference. Simply moving 3-4% from one column to the other is devastating.
No one really believes kamala is a superstar. Even her staff and advisors don't believe it. That is exactly why they don't have her doing press conferences and interviews. That is the difference in the two campaigns. Her campaign advises her not to expose herself unscripted bc they know it could cost her votes/support. They know all they have to do is keep quite and let trump piss people off and run off voters. She listens for the most part. Trump does the opposite and and he cost himself votes simply bc he is shockingly stupid.