There's groups like Run for Something that recruit progressives to run for state and local office
A surprising number of potentially winnable seats are never contested. Let's show up anywhere and everywhere to fight back
If you're worried about Republicans messing with elections themselves, you also have the power to help there too by running for state and local offices. Elections - even for federal positions - are run by state and local officals not by the federal government
That's why I bring up energy. Maybe I should bring up resources, too. Elections cost money just to participate. That said, the guy who owns the Italian sub place I used to frequent won a spot on city council where I used to live, so who knows. I imagine he mostly leveraged a large Italian family and his Italian market, but those are resources a commoner like us can have.
You do your part just being informed, though, and if you ever know anyone with a few thousand to blow, encourage them. I actually should do likewise, but I only know one guy who fits that description and he'd likely do it and lose interest part way, lol