Need Expert Advice to Improve Verbal Score

Dear GMAT Gurus,

I have appeared in the GMAT recently and scored a disgusting 500 (V17, Q42)-First Attempt. I am preparing for GMAT since August 2019. (However I took a break in October 2019 as I had to travel abroad for 2 weeks and then there were Diwali Holidays). Later in Nov 2019, I started my preparations in full swing. I am a working professional and MBA was in my mind for a long time but as I haven't prepared for any exam for more than 10 years, I thought of joining a classroom training. Therefore, I joined a coaching called 'Jamboree'. The teachers were average and kept on rushing the program and they finished everything by the end of September. During Aug-Sept 2019 I spent around 3 Hours/day for studying, including weekends. From Nov'19 -Jan'20, I spent atleast 5 Hours a day and almost whole weekend(~16 hours/weekend). I also took off for 2 weeks before the actual exam on Feb 8th and studied for atleast 8+ hours per day.

Below are the books/sources that I have used for the preparation:
1) OG 2019 and 2020
2) OGVR 2019
3) OGQR 2019
4) Powerscore CR Bible 2019
5) eGMAT Verbal Course- Did only SC part
6) GMAT Club- Did plenty of questions and reviewed expert reviews.
7) Books provided by Jamboree

Below are by past mock results:
Jamboree Mocks:
Mock1--Dec 15 2019--650(V 27,QA 44)
Mock2--Dec 21 2019--660(V 29,QA 44)
Mock3--Dec 24 2019--520(V 17,QA 34)
Mock4--Dec 28 2019--550(V 15,QA 37)
Mock5--Jan 17 2020--610(V 22,QA 42)
Mock6--Jan 28 2020--530(V 17,QA 33)
GMATPrep
Test1---Jan 27 2020--600 (Q-46,V-27)
Test2---Feb 2 2020 --710 (Q-50,V35)--Might be inflated as I got some known questions.
Test3---Feb 4 2020---620 (Q-45,V31)
Test4---Feb 6 2020---640 (Q-50,V27)

I was confident to get atleast 620+ but to my agony I got only 500! Since I performed very bad in Verbal section, I ordered ESR immediately. (Attached).
Clearly, RC is my problem area as I scored null in RC.(This was never the case in any mocks in fact I perfomed well in RC than other sections). I have comprehended the RCs well in the actual exam but I think I was confused in selecting the answer choices and clearly made bad decisions. I am planning to give GMAT again but I will wait till my score in verbal improves to a satisfactory level. I know I have to improve on each and every section of the exam but I think I have to improve a lot in the verbal and IR sections. Please suggest some good ways to improve on my reading comprehension capabilities and some tips to improve on IR as well.

I have read few threads on this forum which says :
1) Read Slowly
2) Comprehend and paraphrase each paragraph in your own words and then write it down on the scratch pad.
3) Understand the tone/geography of the paragraph
4) Understand the relation between the paragraphs (+/- or neutral)
5) Read the question stem and then answer.

Honestly, I have tried this several times but I think over time and under time pressure I often not do it properly. I was having issues in time management as I was writing alot on the scratch pad and almost left with 2-3 questions unanswered. Therefore I dropped writing everything on the pad and started answering questions based on my understanding. I simply read the passage (slowly), comprehend it in 2-3 mins and hopped on to the questions .This strategy was working fine for me and it resulted in 70-90% strike rate in each mocks. But by looking at the ESR, this strategy didn't work in the actual exam. So I need a better strategy to tackle the RCs. Should I start paraphrasing the RCs everytime? Should I follow the same strategy in CR questions too i.e. writing Premise and conclusions on the scratch pad and then only start reading the question stem? Should I take LSAT RCs and CRs to improve my comprehension?. I would really appreciate if someone can point out any potential area in which I can improve. My target score is 720 and I am planning to apply for B schools from August 2020. Preferred B Schools are IIM A/B/C and ISB.

P.S: My Exam day experience was good overall. (Except for the results ). I reached the exam center 1 hour early (the ride to the center was good). I kept myself hydrated and ate adequately on the day before. Also, there was not much disturbance during the exam.

Thanks and Regards,
Antriksh Rawat