“What is the one thing I can do, such that by doing it everything else will be easier or unnecessary?”
This is one of the most powerful focusing questions you can ask yourself. You won’t always find a magic bullet that renders everything else unnecessary, but there is an emotionally stabilizing effect of just deciding to focus on one thing to the exclusion of all else.
There are infinite ways to direct your energy. There is no power like that of consciously directing yours where it’s most beneficial.