Ehh, I could put together a thing that could display several million dots at 60 fps in unity in a few minutes.
(a recent example of some dots I moved) https://twitter.com/LeapJosh/status/1378056437105049603
Not saying DragonRuby isn't the bees knees, I've never used it but appreciate alternatives existing.
Despite that, sprites are the wrong facility for drawing that many dots in unity.