Here is a thematically-related boids simulation from 2006: https://www.red3d.com/cwr/papers/2006/PSCrowdSandbox2006.pdf

Did 10,000 to 20,000 agents at 60 fps. Puny compared to yours, but not bad for 14 years ago! https://www.youtube.com/watch?v=Jpy5rJSVLj8 https://www.youtube.com/watch?v=ZZoy-8xK0YI