How is the Senate gerrymandered? They're elected statewide.
The state borders themselves were gerrymandered in the 19th century to influence the electoral college. That's why for example there's all these very empty northern states like the two Dakotas, Montana and Wyoming that collectively have fewer people than LA but between them they get 8 senators.
As an example: in Texas, there are laws and processes that discourage voting in high-population-density areas that trend less conservative. Can you think of benign reason for a law that bams providing water for people waiting in line to vote in a state that gets really hot?