Hello,
At the outset, I congratulate you on your relentless spirit. Keep it up!
I did not see any official material in your list; I hope that you have covered all the official material. In case you have not, please do so.
Here is an approach that I recommend:
1. Revise all the concept books that you have covered so far.
2. Re-attempt all the questions that you got incorrect in your previous rounds of preparation.
3. Figure out the key pain areas and study some dedicated concept books focusing on the same.
4. Undergo rigorous practice under time pressure; use a material that you have not seen already.
5. Take adequate number of mock tests.
6. An additional tip that I would like to give is to rigorously practice RCs. Often, RCs are underestimated by the GMAT aspirants; being good on RCs helps in overall reading and comprehension speed, something that is at the the crux of the 4 hours long GMAT. Have a fine approach for RCs and then practice 4 RCs per day for a month. You may see some significant improvement on your verbal section.
Rest, after the aforesaid, the score you get, must be your best score. Thereafter, proceed and apply. GMAT matters but is not everything. You can prepare strong applications and thereafter, whichever school you land in, you can perform in that ecosystem and go on to have a fine career for yourself.
All the best!
Maxximus!