Congrats on the perfect Quant score, that's a great achievement! I’d say 675 is a solid score for schools like NUS, NTU and ISB, especially with your strong Quant percentile. However, it might be on the lower side for INSEAD, where the average tends to be higher.
My suggestion for you would be to start working on other parts of your application (essays, LORs, resume). And if you have the time and budget, a retake could be worth it, not just for boosting your chances at INSEAD, but also to improve your scholarship prospects across the board.