Become capable enough that your existence creates practical good.

Good intentions accomplish very little without the capability to act on them, which is why becoming genuinely capable is a moral matter and not just a career one. Practical good requires someone who can actually do the thing, and that person has to be built over years.

Stop separating self-development from doing good. Ask what you would need to be able to do in order to help with the thing you care about most, and start acquiring it.