need genuine advice related to maths

Anyone here who has solved the Black Book? Need a genuine review of its level. I'm a JEE 2027 dropper. Currently doing Allen Leader Modules, Cengage illustrations (which I'm able to solve quite easily), and 2023–25 PYQs. How can I develop Advanced-level thinking in Maths, especially for easy to moderate JEE Advanced questions? Also, which exercises of Black Book should I do before the January JEE Main attempt?