Biden 2020 has to be near the bottom. He took a year with perhaps the most heavily anti-incumbent fundamentals ever seen in a US Presidential election, and made it a close race.
Trump got about the same share that his approval rating was. Biden was a strong candidate who had net positive favorability ratings and so could consolidate virtually all the Trump disapprovers. So unfortunately, there isn't an easy fix for Democrats-Trump voters liked Trump and what he stood for. That's a bit different from 2016 where Trump won a lot of people who disliked him, Hillary being the second most unpopular major party nominee in history was a big factor in the outcome.
