I'm not from the US just to make that clear. I believe in order to realise a general strike, higher union membership is required. In order to reach that you need more people to join unions. As for how to achieve that I won't pretend like I have an answer. I know a bit about unions in Germany but I don't know a lot about the history and legal framework of unions in the US. What I've heard from union representatives in Germany is that when unions are successful in forcing an employer to accept/negotiate workers demands in the context of their workplace the people are like: 'Hey, unions are actually useful and maybe I should be a member.' In order for an action to be successful though you already need high membership at that workplace which is a hard process that requires at least a few people in the workplace that are already on board and are willing to talk to others. Sometimes in secret.
When you want to do a general strike, you also need a quite big warchest since you need to be able to believably uphold the strike for a long time, I don't know how long though. For that you need time to build those funds by having people be union members for some time. Members in Germany are usually required to pay one percent of their income to the union which means that for someone being a member for one year, he can at best strike for 3,6525 days a year. But idk how much of the money is needed for other union costs.
So basically you need more time. Or you don't pay people while striking but they would need to be very desperate to do that.
(Not up to date though)
What does the current 18th district remind you of?