A 2020 Gallup poll found that 46% of American adults read below a 6th grade (11 or 12 year old) level. Many surveys have found slightly better but still worrisome reading levels in the adult population. This is not a matter of Americans being able to read what is on a page, but rather that they do not know how to take in and process information.
Any political analysis that does not start with this fact is fundamentally flawed.
I honestly don't think any more than 10% of the voters Kamala "lost" were because of Gaza. Otherwise there would be millions more votes for the third parties that ran almost exclusively on ending the genocide. The vast majority of these voters abstained from the presidential election and voted down ballot either because they did not like Harris or Trump, or more likely they didn't know anything about either of them and did not feel confident casting a ballot for them.
As much of a farce as 2020 was, the political divide was quite clear. Trump represented COVID and racist cops murdering people. Biden seemed to represent something else. The mass mobilisations and the initial response to the pandemic taught people that and many more of them voted accordingly. The Democrats didn't even try to reach the masses this time around though and so the masses were left confused and aimless and did not vote.