You're probably going to have the biggest impact doing the things you're really good at.
Which might not necessarily save lives.
Or save the planet.
Or sound very sexy.
But a lousy poet, author, singer or whatnot is probably going to have a lot less impact than a great programmer will have.
The thing is that starting anything new from scratch and becoming really good at it takes time.
A lot of time.
And being really good at something is the only way to have any impact at all.
If you're not really, really good at it, then not a whole lot is going to happen.
No matter how badly you want to make this world a better place.
So either you keep doing the things you're already really good at and find other ways to leverage it to increase your impact or you put in the time, energy and resources it takes to become very good at that other thing you're thinking about doing.
It's your choice.
It always is...