is toppr video lectures and its questions enough for fluid mechanics iit jee?

Hello,
Toppr is a very good platform. The video lectures won't be enough unless u practice a lot of mock tests and previous year question papers.
I would suggest you to take the JEE Knockout program by careers360. Check out this link https://www.google.com/amp/s/engineering.careers360.com/articles/careers360-jee-main-crash-course
The course is very affordable at a price of Rs 6999. It will provide smart study material, E-video lectures, constant expert support. You will have frequent mock tests and previous year question papers. You will get 24x7 doubt clearing and detailed analysis of your progress.
Hope it helps