The issue is: "In this moment I am not using anything that I learned".

School is not supposed to tell you how to work. This is more a training. School is based on the idea that "if you stretch a brain, likely it will not come back to the same size". So the idea is to stretch your brain to make it bigger, plus some background and good practices - by example, to learn "how to study, how to learn more".

So yes, school is useful not because the things you study are useful: school is more like jogging. You go nowhere useful, but you make your body better. Just applied to the brain.