IIRC very few people actually make up their mind in the final days before the election.
Right Now is really crunch time already, esp. with early voting and mail-in balloting being the norm rather than the exception. Nobody knows what the error* in the polls will ultimately be, but it's very strange that some people optimistically expect a blue wave to crest. Even those of us here that understand the stakes probably don't fully grasp the enormity of it all. Betting markets currently like DJT by a little**, as we stare into the possible abyss of Trump 2.0.
As you explained, Harris needs a pretty broad coalition (beyond just the base) to win this election. Whether that's pulling in a few 2016/2020 flip floppers or getting some young voters to the polls for the first time ever, it's likely to come down to a small margin in just a few states (out of 7 battlegrounds).
* It's averaged 4-5 percent for presidential elections, historically.
** Nobody knows why, there hasn't been an October surprise. The likely answer seems to be misogyny and racism, along with unchanged bad "vibes" about the economy.