Raycasts and instantiating low-poly dots where it hits is still how we did it, but we did something like this for performance (or at least attempted to):
https://toqoz.fyi/thousands-of-meshes.html
You still get framedrops after 1 million+ dots depending on your hardware, and I do think that using unity’s built in particle system may be as performant or even better, but i havent tested it out yet.