E-paper display is not for inexperienced makers to play with.
On that linked manufacturer,
all 6" are parallel interface (not a great fit), and
some other models have SPI interface versions.
Note that such display requires lots of drive signals, together with SPI.
Probably you had noticed that there are issues (with ugly work-around) on using SPI.
Also Omega2 does consume quite a bit power, especially when WiFi is ON. And note that there is no sleep state and no APM for that.