I know it's late but is there any way by which I can improve mechanics to jee advanced level at least for chapters other than rotation and com. I have a basic understanding of concepts and know the formula .
Try with examples of HCV and then try DCP and do all prev year adv questions, it will be sufficient upto adv level. If time permits try Fiitjee GMP
If you are just concerned about mechanics then it isn’t late at all , even bow you can improve your level to jee adv level .
If I’d had to suggest just one book for it , then no doubt it would have been cengage. It is perfect for even beginners and is ample for adv .
cengage i have , so what to do in that like subjective or objective cause its just toooooo much in bm sharma.
Complete the intext+ concept applications+ back solved example (usually less than 10 questions)
And then you can move on to archive.
Questions of subjective section are very good but solve them only if you have time left
i personally find intext question easy is there anything else in bm sharma
They are easy-moderate , but I recommend it because you said you are weak in mechanics so i though it’s not just the questions that you need but also some theory, so theory without intext is nothing .
If i would have to rank the difficulty of different sections then it will be
Subjective>end chapter solved example>archive>back objective miscellaneous > intext ~ back single correct > concept application