Im creating a game with alot of projectiles, its sort of like a bullet hell game but combat styled.
I currently use cframing to move the projectile. But still after around 80 projectiles per second the server starts to lag.
(the lag is more significant with body velocity.)
I use the PartCache module to optimize projectile spawning, however the hard part is the movement.
I used client hitboxes to minimize the server workload.