You can’t save them all. You can’t fix it all.
There are things that are part of your possibilities and you should pursue them. But some of them might require too much effort, for what?
Given the fact that we all have a finite amount of time, energy and will, how will you spend it?
Life is similar to buying something. You can buy what you can afford, but the difference is that the energy can be different in time and for different people.
It means we need to choose which battle are worth it, which are meaningful, which of them make an impact in the world.