Give me high refresh rates before giving me color. What I don't get is that people say that e-readers are easy on the eyes, but you still get this epilepsy-inducing flicker all the time when changing pages.
Your ereader might be broken. I don't see any flickering when page turning, other than obviously replace current text for the next. Some ereaders take a bit longer than others to change the text, but even then no flickering.
I haven't seen an eReader that does a full refresh on each page turn in years. Kobo, Amazon, and B&N are all per-chapter by default. Maybe some bargain-bin brands still use the old displays or have bad software?
MIP (memory in pixel) LCDs might offer what you're looking for. They're popular in watches like Garmins and some Amazfits.
Newer Kindles have something called a page-turn animation. Not exactly high refresh rate. But no flickers either