knowledge = invested time x the quality of studying

How much we will learn depends on two main things - how much time we spend learning and how well we learn.

So if we have trouble in gaining the desired knowledge, we can ask ourselves which of these two things is the problem?

Are we not spending enough time studying?

Then the answer is to develop better studying habits.

The book Atomic Habits was a great help to us, from which we learned how to actively shape and develop habits.

Do we not know how to study?

In this case, the solution is in more effective learning methods. And the most effective method is active recall combined with spaced repetition.