BEIJING — Chinese leaders hope Washington will tone down conflicts over trade, technology and security if Joe Biden wins the Nov. 3 presidential election. But any shift is likely to be in style, not substance, as frustration with Beijing increases across the American political spectrum. Both Republican and Democratic lawmakers and their constituents seem disinclined to adopt a softer approach toward China, possibly presaging more strife ahead, regardless of the election’s outcome. U.S.-Chinese relations have plunged to their lowest level in decades amid an array of conflicts over the coronavirus pandemic, technology, trade, security and spying. Despite discord on so many other fronts, both parties are critical of Beijing’s trade record and stance toward Hong Kong, Taiwan and religious and ethnic minorities in Tibet and Xinjiang, where the ruling Communist Party has detained Muslims in political re-education camps. The American public is equally negative.