Thanks to gerrymandering, Republicans control congress and most state legislatures.
I doubt that, as a preliminary matter. Republicans have gerrymandered in some states, such as Indiana and Texas, but Democrats have done so in their own stronghold states at least as much. And gerrymandering is immaterial to the control of the Senate.
But even if you were correct, I would still want gerrymandering stopped. It's not fair, no matter who benefits.