A lot, actually.
New York Times did us a solid and actually released their 2020 precinct map in early 2021, not two years after the election took place like they did in 2016. It is not filled in yet in full, as some states are still being put on the map, but it is still very telling nonetheless. Instead of looking at the results at face value (as we had per county as they came in), it is important to look at the change from 2016 in certain cities and neighborhoods, and they are very telling. Some counties shift in certain directions, but many important counties do not shift in those directions uniformly.
Most rural, white areas shifted to the red or did not shift much at all. An exception was the northeast, which presumably was more inclined to come out for Biden than Hillary given the fact that he is an Irish Catholic with deep ties to the region. Most suburban, white areas took a turn to the left. Ethnic suburbanites, however, took a sharp turn to the right. The Polish precincts in Sterling Heights, Michigan continued to move right, the Armenians in Glendale, California moved right by 20-30 points, Mexican-Americans across the country took a sharp right turn, and the Vietnamese in Orange County reverted to their 2004 form in terms of Republican support. Even black precincts across several major cities moved right, although not by a massive margin. This all can easily be chalked up to Trump's populism; supporting small businesses, American workers, and limiting immigration was palatable to ethnic minorities, even as the mainstream media attempted to slander the President as a White Supremacist in the process.
It shows us that it is important for conservatives to hold the line on every issue, stand their ground, and also continue to answer to everyday Americans instead of wealthy megadonors and special interests. You will gain support that way from ethnic minorities instead of mindlessly pandering and virtue signaling to them. We came up short, but we can defeat the system next time if we continue to go down this path as a party. Reverting to 2016 messaging on economic populism will increase the white, rural margins for Republicans, and probably will gain us even more ethnic minorities in the process. In terms of the suburbs, good optics is key, but it is possible that we need to focus more on local issues in the swing state suburbs in order to gain support, which is possible. And making a better healthcare plan helps, too.