Flipping red to blue won’t accomplish much as long as the Democratic party remains a right-wing oligarchic cesspool. The US has two right wing parties and the ratchet effect is very, very real. Look at slightly-left-of-center candidates like Mamdani and Bernie. There is nowhere more left for them to go than the DNC, but the DNC will pull out all the stops to prevent even one slightly leftist candidate from making progress because the party is firmly and militantly right wing.
Short of breaking up the two-party system, which both parties are fighting through the suppression of basic reforms like RCV, we need to find and run strong, leftist candidates that can replace rightists across the board, especially those that make up the majority of the US Democratic party.