Biden’s biggest failure was neglecting the rising fascist movement which will destroy him and many others. Obama made the same mistake with the tea party but him being the first Black President, I imagine, made it more politically difficult to combat with a frontal assault. Biden had all the white privilege in the world and his administration decided to do as little as possible to stop Trump’s GQP movement. No expanding the courts, no real push to dismantle the electoral college, appointed possibly the weakest attorney general in history, and didn’t do much to tangibly improve the lives of everyday working folks during one of the more difficult times in American history. Yeah the stock market and the “economy” are doing great but only the rich give a shit about that stuff and only a few make a connection to politics.
There’s also a laundry list of stuff he campaigned on in 2020 that he made no real effort to even advocate for, such as a public option on healthcare. And most notably missing from Biden’s agenda was a robust anti-corruption legislation package, which would have been massively popular across the political landscape if marketed properly and highly needed.
You can say Biden did some good things as president, and that’s true but on the whole he catastrophically missed the moment with his presidency and that’s partially why we’re in this dark place.