These are tough questions, indeed. Reforming the two-party system will not happen immediately, whereas we need to stop the genocide NOW. Despite winning half the delegates in primaries, Biden is the presumptive nominee. The actual nominee is selected at the convention in the summer, which can override him. The purpose of voting 'uncommitted' or 'uninstructed' is to send the Party and the Convention a clear message that enough voters are willing to let Trump win rather than see a president who has already committed genocide. To have any chance of winning, they have to dissolve that embrace for Zionism.

Anything you can do to amplify this message will help. The website in my first response has immediate volunteer opportunities and further resources for getting the message out.

Third parties in America have a tough time because they need to perform well in earlier elections in order to unlock public campaign financing, whereas the two major parties come with massive donations from wealthy donors. Reforming campaign finance is probably the single biggest improvement the American system can use, but that's a different story.