months on a battery charge"
registered a new account for replying this.. not currently a M5Paper owner but will buy one soon!
I happened to be involved in a ESP + 8951 epaper project months ago, the target is months on battery charge (3xAAA battery).
Main env is done using arduino, and scriptable via Lua. UI is rendered on server, send down to the device during idle & stitched with Lua (it's a calendar kind of device).
repo is @ https://github.com/luan007/em_playbook
hope some code / impl provides some reference ..