reverse engineering a proprietary UART protocol

This sounds cool and all but then

Turns out it was just standard 8N1 115200-baud UART.

I didn’t see any mention of this proprietary UART protocol in your blog and the GitHub project looks like it was as simple as reflashing the onboard ESP32 once everything is wired correctly?

Isn’t that an off the shelf part?

https://www.seeedstudio.com/XIAO-7-5-ePaper-Panel-p-6416.html