Repeal the 17th amendment and balance will be restored to government.
And the 19th
Rather than repeal which will be next to impossible, I suggest nullification, allowing the States Senators to serve out their terms, followed by the State Legislature choosing their Senators. Takes guts, but it can be done, especially if you can get five or ten states working together.
Avoiding the significant dangers of opening the Constitution to progressive meddling through an Article V event.