I built a similar project (https://github.com/taylorconor/inkymon) using an Inky wHAT e-ink dev board [1] connected to a Raspberry Pi Zero, which seems to be the same display as used here.
It's really not fit for this calendar / todo list use-case. It's not possible to get much information density on a 400x300 two-tone display. No anti-aliasing or hinting on the fonts, for example. So you either need great eyesight or very few todos :)