https://fivethirtyeight.com/features/why-the-house-and-senate-are-moving-in-opposite-directions/

«The Democrats’ map in the House is fairly robust, because they aren’t overly reliant on any one type of district. (This stands in contrast to the Senate, where most of the battlegrounds fit into a certain typology: red and rural). While House battlegrounds are somewhat whiter, more suburban and more educated than the country overall, there are quite a few exceptions — enough so that Democrats could underperform in certain types of districts but still have reasonably good chances to win the House. This differs from Hillary Clinton’s position in the Electoral College in 2016, in which underperformance among just one group of voters in one region — white working-class voters in the Midwest — was enough to cost her the election.»

(I stopped reading about here. The details on 538 usually support the summary.)