The 2020 Election Steal didn't affect most non-Presidential races because NeverTrump Republicans taking part in the shenanigans likely held as a condition of cooperation that down-ballot races be affected as little as possible. With perhaps a few exceptions, the votes on other races were as fair and accurate as they would have been otherwise.
Rhetoric and greater agenda notwithstanding, it really was a targeting of President Trump personally. NeverTrumpers and "Resistance" really do believe he would have become--and will become if reelected in 2024-- the next Adolf Hitler.