Hey,

IISERs consider KVPY and JEE score, but not NEET. IISER also gives admission to students on the basis of its own aptitude test for science stream students who pass class 12 with marks equal or above the cut off percentage. If your concepts are strong, then it will be easy for you to clear the IISER aptitude test.

You can also take admission in IISER through SCB Channel (Percentage in State and Central Boards). Students who are appearing or have passed (10+2) level with science stream with marks equal or above the cut off percentage in their respective boards are eligible to apply.

Students applying through SCB channel will have to appear in the IAT (IISER Aptitude Test) which will be conducted at various centres across the country.

If you are interested to do research in basic sciences, then obviously IISERs are the best option in India. IISERs were made for the purpose of doing research after all the IITs(except one or two) failed in doing good research in basic sciences. IISERS are doing a great jobs so far it's inception. If you see the latest Nature index ranking 2020, IISERs have done well than most of the IITs. IISER Kolkata, Pune, Bhopal all there in the top 10 institutions in India in Nature index ranking 2020, with IISER Kolkata leading them all at Number 5.

Academia (Research): After doing a PhD, post your BS-MS course, you can join any CSIR labs or University or research lab as a staff scientist or principal investigator. Academia (Teaching): The IISER graduates can take up a teaching job in any school/University after qualifying the requisite exams like UPSC.

I hope this helps