I mean reading all the analysis, leaks, and think pieces, and committing to viewing the Harris campaign in the best possible light, the final story is:

Harris knew her best shot of winning was to emulate Biden's 2020 platform, but panicked because she was starting so far behind in the polls. This made her open to influence, and because the only people she actual knows are Blue Dog neoliberal shitheads she ran Hillary's campaign to a resounding loss.

And that's the KIND version.