Looks like Waveshare has a E6 full color ePaper/eInk/EPD display in 3.6" and 7.3" but not yet in 5.83":

"5.83inch E-Paper Display (G), E-ink Display, 648 × 480, Red/Yellow/Black/White, SPI Interface" https://www.waveshare.com/5.83inch-e-paper-g.htm?sku=32584

Full color, except for certain shades of blue