Being decisive often means deciding between two “better” options.
Going through that prioritization is hard. Every decision you make affects a complex system. Nothing is on an island, and my assumption is that you intend on doing the right thing.
It is rough to know that even a little attention to that other option would mean some good in the world.
That is a trap. Eliminate it from your consciousness.
I know “no” when you know the cause is good is painful.
The alternative is a disservice to both. Letting something fall off could lead to someone else picking it up. That can’t happen if you are in the way.