Politics is the art of the possible. At the moment you have no chance of selling anything called socialism to the majority of American voters. It's true that they have been taught that communism and socialism are the same thing (lie: they're not) and that socialism will mean their lives will get worse (lie: probably not). It's true that Fox News has taught them to fear socialism like the Devil. You aren't going to undo that in 75 days.
So go with the possible. Bernie Sanders would have been an excellent president but was outmanoevred; Biden is old and a patrician with a Corvette but...
Have you seen his speech accepting nomination? If you haven't, I suggest you watch it. Before I saw it I didn't think he had a chance in hell of winning.
Now I think there's a possibility.