Nope! For JEE Advanced 2021 you have to qualify the JEE MAINS 2021 then only you will be eligible. Every time you appear for JEE ADVANCED you have to qualify the JEE MAINS.

For JEE MAINS preparation strategy visit the link provided below:

https://engineering.careers360.com/articles/how-prepare-for-jee-main

For JEE ADVANCED preparation strategy you have to visit the link below:

https://engineering.careers360.com/articles/jee-advanced-preparation-tips-physics-chemistry-and-mathematics

I hope this answer helps. All the very best for your future endeavors!