Chipping in my experiences, I bought Seeedstudio epaper with ESP32c3 chip. I think I flashed some wrong code there via OTA upgrade and I thought I bricked the device for good (No serial connection anymore or nothing)
I then finally took the display apart and removed the ESP32 board from the main battery/display driver board and then tried flashing.
Flashing only the ESP32 board separately worked at first try.
I remember I read somewhere that some IO pins may sometimes be in some conflicting state that prevents serial link from working or something like that. So maybe the issue was that previously flashed FW and its configuration was not compatible with the Seeed battery/display driver main board.