hi aryan,

I hope you are doing well. Regarding SRMJEE vs VITEEE vs BITSAT

Level of toughness of the exam :

BITSAT >> VITEEE > SRMJEE

Level of institute you will get after clearing these exams

BITS PILANI >>> VIT > SRM

So, Yes BITSAT is toughest among them but it also offers you a seat in the best private engineering college of India and there is a very good competition for a seat in BITS.

I hope this answer will help.
All the best for the future!!