Gotta start local and work your way up. The system is fundamentally flawed. There are many problems, but the most fixable is the voting and representation systems, which can usually be changed at the local level through referendum. Approval Voting is an easy fix with big impact and when applied to multi-winner elections you can use a proportional variant to get proportional results in the legislature. Both of these changes would reduce polarization and make it easier for third parties to get in office. With more than two parties in power, the parties have to start working together and compromising on things, instead of just obstructing until they’re the majority and then jamming through partisan bullshit. But you gotta start local. Run a referendum campaign, switch your local elections to Approval, and work your way up.