Technology connections had a video showing a large e-ink playing video, and it was 3-5FPS, so unless your use case is "videos and games" e-ink is already plenty fast.
It's even faster if you let it manage its own pixels and only update parts of the screen that need to be redrawn. Can't play videos like that but scrolling a spreadsheet becomes much faster.
Have you actually tried? Do you have a video of this? Because as far as I know, and I actually work with electrophoretics, physics limits the speed of the ink. I hope you're not confusing something like A2 mode with actual display updates.
It's even faster if you let it manage its own pixels and only update parts of the screen that need to be redrawn. Can't play videos like that but scrolling a spreadsheet becomes much faster.