I’ll wait until the full results are in but it does seem a few Republican states suffered from the “gerrymander cliff” problem.

In a pack and crack gerrymander, you pack a lot of your opponents into a small number of districts, and give your own party districts with a modest majority.

e.g. suppose your state, per the recent election, has about 50-50 R and D voters, and you have free reign to redistrict into 5 districts.

You’ll get out the demographic maps and work out how to draw boundaries so that the great bulk of the D voters are in one district like:
A: 90% D 10% R
B: 40% D 60% R
C: 40% D 60% R
D: 40% D 60% R
E: 40% D 60% R

So despite the voters being even, you’ve garnered 4 divisions versus your opponent’s 1.

But what happens of there is a 11% swing. Suddenly, you’ve got nothing.