I suggest buying M5Stack PaperMono instead. It's an esp32 board with an eink screen and a battery. I bet someone will make an open source firmware for it

> M5Stack PaperMono

Is that actually a product intended for consumers though? Looks more like a development board than a product for "normies", like the Xteink stuff.

They still run the same thirdparty firmware. Seeed Studio has the reTerminal Sticky too.

M5 device are cool but they do have that, as ugly as it is useful, functional diagram printed on the back...