I'm not sure how one would come to that conclusion. Biden is regarded as a centrist, e.g.
https://www.nytimes.com/2020/12/19/us/politics/biden-cabinet... or
https://www.latimes.com/politics/story/2020-08-12/harris-bid... , so there's no love lost between his administration and the progressives. They might get a few things they want but Biden and the mainstream Democrats are probably going to keep their distance for the most part.