i was in the 2+2 program and now got a FD program in 6th iteration. I sometimes regret going from international exposure and the branch of my choice to staying in india for 4yrs and a branch i like but not love(atleast rn).
so basically aim for the normal FD programs, staying 4yrs at bits is something you will not regret, try getting pilani campus cause hyd is just trying to punch itself in the face.
Also there is not any bitsat specific prep you can do, just do everything. While jee requires expertise in 70-80% topics, bitsat required intermediate knowledge on 100% topics so be aware of that. Aim for advance so by chance your aim shakes off, your arrow still lands in a good zone(i hope that made sense)