I think we can all agree that as pilots we all have a basic level of understanding. My post is simply giving people the heads up as to the level of detail needed to pass the exam. It has nothing to do with my personal level of knowledge.
If you wish to study the entire EASA question bank, you will simply waste valuable time and effort. If, however, you study the Qatar question bank, many of these questions appear in your exam (depending on which exam you are given).
Any questions that appear that were not in the Qatar question bank, were of a similar nature and level of complexity. I personally had 50% from the question bank, the rest I had never seen before. However, they were of a basic nature.
Take it how you will. Just sharing my experience and good luck.