You have a small amount of room for improvement on quant, but most of your improvement will have to come from the verbal.
These two articles should help to get yourself into the right study mindset (in terms of being able to answer GMAT questions, not just know the lessons):
https://www.manhattangmat.com/blog/inde ... lly-tests/http://www.manhattangmat.com/blog/index ... -the-gmat/Because you have already gone through the book material so many times but are still having issues with the material, you may need some outside help in the form of a class or tutor. In particular, you say that you know the material in the books but are having trouble applying it in testing situations - that is exactly what a class or tutor would help you to overcome.
It sounds like you already know that it was a bad idea to take all of your CATs in a short period of time, but read this:
https://www.manhattangmat.com/blog/inde ... many-cats/I'd like to know more about your strengths and weaknesses in order to advise you further. Please use the below to analyze your most recent MGMAT CAT (this should take you a minimum of 1 hour):
https://www.manhattangmat.com/blog/inde ... ts-part-1/Figure out your strengths and weaknesses as well as what you think you should do based on that analysis. Then come back here and tell us; we'll tell you whether we agree and advise you further. (Note: do share an analysis with us, not just the raw data. Part of getting better is developing your ability to analyze your results - figure out what they mean and what you think you should do about them!)
In particular, you mention fluctuations in your verbal score. Tell me any ideas you have about why this is happening. Timing problems? Holes in your foundational skills or knowledge? Mental stamina issues?