I do think cheating is 100% certain in this election for many reasons, but the "devil's advocate" argument that a Democrat can make to explain this seeming disparity in the stats is that Orange Man is just very polarizing. More rural people came out for Trump (why he won more counties than ever before) but also more city people came out for Biden (their explanation for why Biden got so many votes).

In and of itself, this factoid is very interesting, but not a kill shot or proof of anything other than a deep urban/rural divide right now.