I am also looking forward to this. Is there any ETA?

I have finally made it work see the repo
https://github.com/leCandas/M5Stamp-C3

There also M5Stamp-C3U. (C3 discontinued ?)

the only difference is c3u does not have a serial chip on, you flash directly to esp32 c3

thanks for information. but without serial chip, no upload by USB ?

You need CDC serial emulation. Check this: https://github.com/platformio/platform-espressif32/blob/develop/boards/adafruit_feather_esp32s2_tft.json#L10

This is the output of pio device list in CDC mode

Hardware ID: USB VID:PID=303A:1001 SER=60:55:F9:57:B6:10
Description: USB Serial Device (COM6)

Any confirmed platformio.ini configuration for the C3U?
Thanks!

@ThomDietrich https://github.com/platformio/platform-espressif32/blob/develop/boards/adafruit_qtpy_esp32c3.json
should work since it is the same from board design.

Any update ? I have tried to use it today, but this doesn't look to be officially supported.