You working for them would most likely not push them from failure to success. It would perhaps make success marginally more likely, or perhaps decrease schedule overruns slightly. Or perhaps make not much of a difference at all, depending on how screwed they are.
Of course, the estimate of impact also depends on how you value humans. If you value all humans fairly equally, then Americans who had a job until fairly recently (ie those eligible for unemployment insurance) are already fairly well off compared to the people who benefit from more malaria nets. Especially since their unemployment benefits would merely be delayed, not lost.
Lots of people value those closer to them higher. The most prominent example are family and friends. But valuing compatriots higher is fairly common as well.
Of course, you can give more than 10% of your income as well.
In absolute terms, perhaps. But if you are moving away from taking jobs out of self interest, and into doing something for the public good; you might as well check out https://80000hours.org/ and pick the job that has the most positive impact.
My guess is that working any kind of 'normal' programmer job and giving 10% of your income to an effective charity would beat out enduring the bad boss in New Jersey.