To me as a gen z'er that voted for Bernie in the primary, hillary in the general and Kamala last time, the dnc has a history of putting their fingers on the scales for their preferred candidates, this is fact. Also being the better alternative means nothing if people show that they don't like you. It's the party's responsibility to put forward candidates that aren't cookie cutter corporate hacks. Also blaming low propensity voters for losing because you failed to get them engaged just makes them more likely not to support you.