The best e-ink tablet I've tested was not made by Amazon or ReMarkable | ZDNET
Amazon.com: Three Color 2.9inch E-Ink Display Module (B), 296x128 Resolution 3.3V/5V E-Paper Epaper Display Screen Red Black White Tri-Color Compatible with Raspberry Pi/Arduino/STM32,SPI Interface, Full Refresh : Electronics
Amazon.com: waveshare 2.7inch e-Paper Module, 264x176 Resolution 3.3V/5V Two-Color E-Ink Display epaper Screen Module SPI Interface for Raspberry Pi 4B/3B/3B+/2B/Zero/Zero W,Jetson Nano,Support Full Refresh : Electronics
Amazon.com: waveshare 7.5inch E-Ink Display HAT,800x480 Pixel Black,White Two-Color SPI Interface E-Paper Screen LCD for Raspberry Pi 4B/3B+/3B/2B/Zero/Zero W/Zero WH and Jetson Nano no/Ard/Nucleo : Electronics