In Democratic districts, net incumbent approval has plummeted by 11 points, from +8 approval to +3 disapproval. In Republican districts, incumbent approval has gone down only 4 points. You see the same results when they ask a question about warmth of feeling toward incumbents: It's down 7 points in Republican districts and 9 points in Democratic districts.
This isn't good news for Democrats. It's true that attitudes toward the Republican Party have taken a bigger hit than attitudes toward the Democratic Party, but attitudes toward actual incumbents are exactly the opposite. And in elections, that's what matters.