The problem with their actual campaign promises is they weren't always self-evident to the average person why they were the things they'd want, which you touched on. "How does taxing billionaires deal with greedflation? I don't smoke weed—why should I care about that? Why are my groceries so damn expensive, now‽ I remember when gas was cheap. What were the promises, again?"

I agree that the issue they had is their campaign promises weren’t self evident to the average person. It seems they had to choose to either A) give all of America an economics lesson so they understand their goals, or B) lie like the GOP does and make up a scapegoat to blame inflation on. A) isn’t feasible and B) makes them look untrustworthy to anyone who understands the situation enough to see they are scapegoating.

I think the real problem the Democratic Party faces is beating the GOP without becoming the GOP. There’s a lot of voices online pushing for Biden to execute Trump and do things that we would only expect Trump/GOP to do. I wouldn’t be surprised to find out those voices are bad actors trying to normalize Trumps behavior.