@ranaday789 With the pi I want to squeeze every bit of performance I can and 64bit can be slightly faster than 32bit if the emulator is properly made for it.
In my tests, I'm not sure if it's 64bit or if it's bullseye (I didn't try 32), but I got a significant boost with lr-snes9x on my pi3b+. This is with the few alterations I did to the retropie-setup script so it's not properly optimized.
Here are some benchmarks though they're from benchmarks apps and not emulators:
https://www.phoronix.com/review/raspberrypi-32bit-64bit