I think its worth remembering that viewing through the prism of our own priorities isn't always the best analysis.
On a very small level the number of young people voting Democrat reduced, whilst the older age group increased.
On the basis of comments on FWR implying all about young people have been captured and older people knowing the reality of biological sex, then you would think the numbers would be reversed. ie lots of young people supporting GI politics and older voters alienated.
The biggest change in voting (apart from the 11 million democrats who couldn't be bothered to vote), was the Latino/Hispanic men, some of whom are now saying they dont care about the racist characterisation of them being drug dealing rapists, what they want is a low state free enterprise system. (Some commentators who may or may not be right, say that recent migrants to the US fear the experience of "communist" regimes in their country of origin far more than load mouth bigoted racist statements by publicity hungry entertainers.)
I think apart from the smug we are so left we are always right attitude of some Democrats, the big problem was that the party system failed.
I heard one quite senior democrat saying that basically they thought Biden would stay and get elected and then either become too ill or even die so that they Harris could just step into the post of President.
In taking this gamble, and not bothering with primaries (is that the right term?), some existing Democrats felt taken for granted, snubbed or whatever, by the establishment.
So 11 million chosing not to vote Democrat maybe as much about that. Presumably even if they had doubts that a Black Woman could get elected they would turn out to vote to try and make it happen. But they chose not to vote. Chose to risk Trump getting in.
Why?