The boolean column in your Courses table is User Specific, which means that the data in that column is only ever available to one user at a time - which is the user that is signed in (or the user that you are viewing as in the App builder).
So what you have at the moment is most likely giving you correct results - but only for the user you are viewing as. Unfortunately there is no way to summarise/rollup user specific data for multiple users.
So if that is your goal, I’m afraid you will need to re-think things a bit.
Doesn’t works because if I activate the value with a user, and I change to another user, is the same result. For this reason, in the user table, the count is always the same number for all users (and graph display always the same number, obviously).
I suspect that it’s working, but you might be not understanding or misinterpreting what you are seeing. When you are working with user specific column values, the results that you see in the builder can sometimes be a bit misleading or confusing.
Open your published app on your phone or in a web browser, sign in as one user and check the results. Then sign out and sign in as a different user and see what you get.