Did you know AOC has actually stopped supporting far left challengers to more centrist candidates? And that while seats were flipped everywhere, seats in the heartland and in prime swing states were won through a concerted (and skillfully done) effort by the DNC by way of a two pronged approach of promising useful reforms as well as a rebuke on trumps actions as president.
this is of course exactly the same strategy they are implementing with Biden. Yes there were a few seats flipped by far left candidates but of the 40 won by democrats the vast majority were won by people who deliberately cast themselves as pragmatic democrats who could get things done. Not hyper ideologues