Biden didn't actually expand the coalition, and the truth is there was no campaign the Democrats could have won that would both totally neutralized such an attack and still have been distinguishable from the GOP.
In this day and age, it's absurd for the U.S. government, under any president, to still be obsessed with trying to put the rich back in power in Venezuela and Cuba.
And Biden would probably have won by a larger margin if he'd said something like "hey, I'm NOT a socialist, but all Bernie and The Squad are pushing for here is the revival of the New Deal, but this time without the exclusion of black and brown people".
Trump's fear strategy only worked to the degree it did because Biden didn't stand up to it, didn't call it out as bullshit.
The fact remains...the Left never deserved the treatment the Democratic Party inflicted on it this year. We're not the enemy, and we're not the damn problem.