There exist people who think Biden had a better shot and replacing him with Harris was a mistake? Did they not look at his approval ratings earlier that year, then look up what that's historically meant for presidential re-elections? Dude was gonna lose, and by the time of the replacement he was likely gonna get crushed. The replacement probably helped down-ballot races, given how badly Bien was likely to perform, so was a good idea even though she lost.
Like, yes, it was per se bad but people blaming that for the defeat is... confusing to me.