One person can do very little (unless they do have billions of dollars at their disposal).
Why not seek out an activist group in your area and join them? It takes a lot of resources to mobilise people on the streets, carry out campaigns etc. Nearly always they will need support staff on back end processes and systems. Maybe they need your specific skillset, or maybe they just need other parts of the organisation. You won't be single-handedly saving the world, but you will be part of a team that maybe can achieve that.
This might take you out of your comfort zone, but hey, what have you got to lose?
