Is there a way I can step physics customly?

I want to freeze Roblox’s physics during runtime using a method that works in the roblox client. This is because I am creating a simulation, and I want the simulation to adjust in synchronization as the physics. I know I could bind the physics updating to the simulation step, but I want to be able to customize the speed of the simulation too.

workspace:StepPhysics() seems to be a studio function and doesn’t work during runtime.