Sadly the Republican's "grassroots" orgs get tons of funding from the oligarchy, while any grassroots orgs on the left get none... Without funding I don't know that there's much we can do. Personally I worked my ass off in progressive politics for a few years after Bernie, but unfortunately eventually had to move on to something that can actually pay. Now I've moved as far away from the South as I could, bought a gun and ammo, and a couple weeks worth of emergency food. I don't see any way out of this without it getting really bad. End stage capitalism is rough.
Besides the fact that each new generation is more progressive than the last one, honestly my only hope is that as AI starts taking their jobs, and the oligarchy keeps squeezing more and more out of an ever shrinking upper middle class, that eventually they'll start joining us and voting progressive. Like right now 50%ish of people own nothing... What about when they've squeezed every drop out of 75%? 90%? At what point do the people in their golden bubbles start realizing they've been getting screwed all along too? Hopefully it's before millions die in the streets.