Simulating coffee beans falling into a warehouse using a particle system

Hello everyone!

I am working on a simulation of coffee beans falling into a storage warehouse using a particle system and PBD (Position-Based Dynamics), but I am encountering some issues. The coffee beans are not filling the warehouse as expected, and the physics of the beans at the bottom are incorrect.

Is there a way to make the coffee beans rise more slowly and follow accurate physics? I have checked some YouTube tutorials on PBD, but they are not detailed enough to achieve the desired simulation.

What adjustments do I need to make in order to improve the physics simulation? Should the particle and mesh sizes be accurate to real-world measurements?

You can watch the video below to understand better.

Please help me. Thank you!