They’re expensive but not really overpriced. Boox tablets are essentially Android tablets with highly specialized screens.

Eink screens (particularly high refresh rate screens, like what you’re looking for) are still a relatively new tech and don’t have the cost benefits of more matured technology like LED/LCD. The cheap eink screens you see have very slow refresh rates and don’t offer the same pixel density, with harsher gradients.

I’d reccomend getting one used, or waiting for a seasonal sale. I’ve had one for a while and I love it.