The biggest problem with her campaign was the one thing it was impossible to fix - the amount of time. Everything else is nitpicking and wish-casting.
And that's on Biden and his team, mostly. I do give credit to the party for actually forcing him out. That's a hard thing to do, and it's exactly what R's ought to have done to Trump a long time ago.
I disagree. When she announced her candidacy she largely had the election in her pocket. Had she run the same campaign for longer her support would have just been even lower. The only reason Biden stepped down was because the ruling class in the DNC made the call. The party voters were very vocally against him the whole way.
I'm a bit confused why you think republicans would toss aside a winning candidate. The party is laser focused on winning. That seems to be sadly a major difference. The DNC seems overly concerned being as milquetoast as possible and to simply assume a moral high ground.