The Dems lost with Hillary and decided it was a fluke rather than a property of their electorate, so Biden doubled down with Harris. If you believe that leadership means getting out in front of your public and bringing it along, that was not necessarily a mistake ethically even if it may have turned out to be tactically. But the point has been made that if that was the plan then Biden had to give Harris at least as much or more profile in his admin that Obama gave Biden, and it was never even close. One can also argue that if it was foreseen that a win was so critical in '24 and the Dems were absolutely set on a woman, then pick a white woman and least save your self that half of the battle. In any case, there are a lot of way to slice and dice this history on the continuum of what should have been done in 2020 that cast the die for '24. But the other factor is that I think a lot of people thought Trump would either have gone away to jail or at least gone away instead of holding his grip on GOP.
Everybody needs to suck it up, go find someplace to use your efforts help build US civil society for the next few years and make a contribution to holding it together.