Here is second hand Oynx Boox Tab Ultra C (Color eink) in CEX, Limerick, Ireland. €500.
A 10.3″ screen, but based on a 1404×1872, so 227 PPI/DPI (same as Elipsa) in artefact ridden mono. Colour (or Artefact free mono) is 702 x 936, so 113.5 dpi
Very bright display lighting.
Note how dark and washed out it is. Oddly less matt than most of my mono eink screens. S/H on
Amazon Germany €563 + shipping
If you want to avoid colour artefacts you have to use it at 113.5 dpi in mono, because the 227 dpi underneath panel has
R G
G B
matrix of translucent coloured dots that don't fill the pixels (so as to make it a bit lighter, but also makes colours look faded. Obviously a Colourised Sage would be 150 dpi and pseudo 300 dpi.
Taken earlier this week. A TCL Nxtpaper 11 (10.9″, approx 16:10 aspect, Nxtpaper 2.0) or TCL Nxtpaper 14 (14.25″, 3:2 aspect, Nxtpaper 3.0) is much cheaper and better.
Note that LCD and OLED vendors, even using subpixel addressing to sharpen the text, only ever quote the colour resolution. All LCD panels (inc QLED) are really only mono and filtered (QLED only has red and green "quantum" dots with a blue back light), reducing the resolution to give the claimed resolution.