620 (Q49, V26) W/ESR: How to get 680+ on Test Day

Hello All! After 3months of studying, I wrote my GMAT this week scoring a 620 (Q49, V26).
My previous score from last year was 610 (Q47, V27). After studying around 20 hours a week, I was very discouraged and disheartened by the 620 score.

As for my study plan, it was to work on my fundamentals first, then work on practice questions and mock exams.
Resources used:
1.) E-GMAT Verbal Online
2.) Math Revolution
3.) OG 2016
4.) GMAT Club Grammar Book
5.) Veritas Prep Practice Exams
6.) GMAT Prep Question Pack 1
7.) GMAT Prep Free, Exam Pack 1/2

With SC being my most glaring weakness, I started off with the E-GMAT Verbal online eventually going through all of the SC and CR section in the first month or so. After this, I did practice a little bit on OG and saw improvements in my SC accuracy. I then eventually signed up for MathRevolution as a goal to consistently hit the Q49/50 mark. I went through this program within a month and was hitting Q48-50 consistently in all my practice exams. I realized that the questions were not difficult and for Quant, it was about re-learning the fundamentals and avoiding silly mistakes. With this, I turned back to reviewing my verbal while taking mock exams every weekend.

Mock Exams:
GMAT Prep 1: 590 (Q47, V25) - Original CAT before any studying
GMAT Prep 2: 600 (Q47, V26)
GMAT Prep 3: 640 (Q49, V29) - 3 weeks before exam. Right after finishing Math review
GMAT Prep 4: 680 (Q49, V34) - After a week of verbal review
GMAT Prep 5: 640 (Q48, V29) - 1 week before exam
GMAT Prep 6: 650 (Q48, V31) - Day before exam

I also took just the Quantitative portion for Veritas Prep Test while I was going through Math Revolution
Veritas Prep 1: Q46
Veritas Prep 2: Q47
Veritas Prep 3: Q49
Veritas Prep 4: Q48
Veritas Prep 5: Q50

From my personal observation and experience I feel very confident on consistently hitting Q49 and on doing so on test day. I understand Q50/51 is on another level/tier so I don't believe it is worth my time to try and improve Quant at this point. That being said, my Verbal is still terrible and although I feel more comfortable after going through so many problems and covering all basic fundamentals, it is obvious I still have some serious flaws when it comes to SC especially. I do feel as though my CR and RC are on a decent level. My CR has ranged from 32-38 usually while RC has been between 32-36. Unfortunately, my CR went horribly on my exam and felt that it was much harder than the GMAT Prep or anything else I have encountered. Finally, for SC, I also felt as though the real exam was harder than what I have been practicing.

I am now looking for advice on how I should refine my SC skills to get it to a respectable level. I need to improve my accuracy and speed for SC to have a chance to improve my Verbal. MY goal is to consistently hit V34-36 so I have a shot of hitting 680+ on test day. I ran out of time before the exam last time to go through all of OG 2016 SC so that will definitely be part of my study plan for the next exam which I am planning to take either the end of November or early December.

If anyone has any advice on how I can improve (SC especially) or anything else, I would appreciate it!
Thank you for reading my long post and thank you in advance for any help!