I don't think the US will have the time for a "post-mortem", this is not a bug that just disappeared/was solved because Trump is no longer president. More people voted for him in 2020 than they did in 2016, the racist things that he has said and done have not come out of no-where, he had (and still has) a strong support behind him, and that support won't disappear over night.
Have they deterred business with China in favor of moving that business back to America? Or have they just passed the price along to the American consumer?
It would of course be ideal if EU and all democratic countries got together, but they (just like Biden) unfortunately have no interest in doing so. Biden believe that it’s USA’s self-interest to see China prosper.
You can also see that China’s GDP growth (in 2019) was the lowest it’s been since 1990 (2020 will no doubt be much lower), and their reputation around the world is at an all-time low.
It’s also worth noting that the administration did a lot more to stand up to China besides tariffs (but tariffs that force companies to leave will of course hurt them the most).