I don't know Datashader that well, but from what I understand, it generates an image from a set of primitives (e.g. points), and then allows you to interactively inspect that image. It does not re-render the points on every frame like Fastplotlib/Pygfx does.
Depending on your GPU, you can render say 1-50 million points smoothly. Also see e.g. https://github.com/pygfx/pygfx/discussions/819