Continuously prepping but scores keep dropping (700, 650, 620, 600)

I am absolutely shattered today after receiving the scores for my 4th attempt this year for the GMAT. I feel completely lost and I don't know what I should do next, considering that it'll be my final attempt for the year if I retake it yet again.

Breakdown of my attempts

Attempt 1 (15/5/2019)
- Full-time studying for 1.5 months
- Prep used: OG, GMAT Prep (1-6), Economist
- GMAT Prep scores: 650-670
- Score: 700 (Q44, V42)
- Reflection:
- Overall: I managed to finish both quant and verbal on time during the test, but felt there were many instances where I skimped and took a leap of faith, especially in quant. Overall i felt there was a an element of hoping that I'll be lucky.
- Quant: I felt that there were many concepts that I was still rather weak in, eg. Factors, Perm&Combi, Arithmetic Properties. My ESR showed that I was particularly weak in Geometry and Algebra, but that's because not many P&C questions came out, and most of the questions of higher level that I got wrong were Geometry/Algebra. So i decided that I would go back and practice more OG questions, and find out how others are solving questions on gmat club.
- Verbal: I didn't really 'feel' anything after the test, because for verbal I literally went in thinking that I wasn't going to score too badly.

Attempt 2 (20/6/2019)
- Full-time studying for 2 weeks (less organized and less hours per day)
- Prep used: OG, GMAT Prep, Previous notes, GMAT Club
- Score: 650 (Q36, V43)
- Reflection: Thinking that I got a 700 in the first attempt, I believed that practicing more OG questions would naturally get me a higher score (very silly). But as away for a holiday between my first and second attempt, and by the time i got back to work I had just 2 weeks or so to prepare. I felt I became slower, and I struggled with Quant very early on in the test (first 10 questions), and by the time I got to verbal, I knew i was going to score less. I blamed it on my still rather weak math concepts, like I never REALLY understood the theories behind some of the arithmetic property questions.

Attempt 3 (3/7/2019)
- Full-time studying for 2 weeks (more dedicated to studying, but had many errands/duties in life that I needed to attend to in the midst)
- Prep used: OG, GMAT Prep, Previous notes, GMAT Club, Manhattan
- Score 620 (Q35, V41)
- Reflection: The Manhattan books significantly helped me understand some of the Math concepts much better. But what I lacked was constant day-day practice. I learned new methods to solve math questions that I wasn't confident with, but suffered in terms of timing. I ended up not being able to finish my verbal in time (hurried through some questions, guessed 2 questions at the end, missed 1 question), and I suffered too for quant in terms of timing. I was also unable to answer many arithmetic type (prime/factor etc. questions in the beginning, as well as some complex word questions in the middle).

At this point I felt maybe I was being overly optimistic about my abilities, and that I was rushing it too much to retake the exam in such short successive periods. I decided that I would hold back on my plans for application, and take some time to do constant work everyday, and make sure I was fully well versed with the quant parts that I am not familiar with.

Attempt 4 (15/8/19)
- Part-time studying (I have a full time job)
- Prep: OG, GMAT Prep, Previous Notes, GMAT Club, Manhattan
- New prep style: Error logs, more detailed analysis of each question, made sure I was very well versed with my weak math concepts.
- Score 600 (Q41, V31)
- Reflection:
- Verbal (started with verbal this time): I feel I knew what went wrong. After about 20 questions (all of which I feel I did very well), I felt the the standard really jumped on question 21. It was a long RC question which I had trouble understanding at first read. I ditched my new approach to RC questions which I used for the previous 20 questions ( write down simple info, comparisons etc.) and tried to re-read it many times. Seeing that I have wasted 2 minutes on the passage, and that RC typically carries 4-5 questions, I was unwilling to give up and skip the question. I ended up taking far too long for the question, and ended up skimping on the final 10 questions (pretty much guessed the last 6). So i knew my verbal was down the drains. I previous thought with my improved understanding of the verbal section ( made a lot of improvement in C/R), I would get a V46-V47 at least, I was completely shattered.
- Quant: The first question was difficult and I didn't know how to solve it (algebra/decimal/percentage question). And from there it was actually rather smooth. But this time I reminded myself that I would need to make a best guess for questions that I was going to be stuck with (around 2-3 questions max). The other questions felt easy to me, and I felt I got most of them right. But the overall score showed otherwise. I didn't know what went wrong, I will be getting an ESR tomorrow.

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My dilemma:
I feel really confident about the technical part of verbal, and have scored consistently above 90% in the OG. But feel i tend to take too much time for C/R questions as it was my previous weakness. I feel I can rectify this in the next two weeks.

For quant, I feel I am running in circles here. The only difference I could feel between my first attempt and subsequent attempts is that I am making less guesses, I am trying to take less short cuts, I am estimating less, and trying to solve each question a lot more. This hasn't improved my accuracy at all, and I felt having a single, systematic approach to each question, and taking enough time for each question didn't really work for me. I started with the Economist prep - which teaches short-cuts and estimating answers really well, but mathematical principles weren't the focus. So now I feel although I am better with the principles behind these math questions - I am doing worse!

I am not sure If I should schedule another test in two weeks. I feel I am good enough to score higher than my first attempt and still have a conscious tendency to refuse to believe that I am anything less than that. I know I am stubborn, but at the same time I am feeling increasingly less confident about my real abilities. I knew that I was half-hearted for my 2nd and 3rd attempt and I deserved those scores. That led me to believing that if I quiet down and go back to doing some real studying, I should be able to score better, but my 4th attempt showed otherwise. I am really lost, and am trying to find someone who could shed some light for me - is there something that I am clearly not seeing?

I know I sound stupid but this is exactly how I feel, without any cover up. I am dejected, but inside I feel I am ready, in terms of knowledge, and am unwilling to accept defeat. I don't know if I am being oblivious and overly confident..I am in a hurry to get this GMAT done, and now I am faced with having only one attempt left for the year. And four attempts left in my lifetime.

I am aiming for a 720-730.

Please help, and share your experience if you've been through a similar situation, please.