The firmware can already be used as a serial over WiFi adapter through the Web CLI.

You do not need to connect a separate USB-UART adapter to it: simply connect the ESP32S3 UART pins directly to the board’s TX, RX, and GND pins.

Any ESP32S3 board could do it, see README for different types of supported devices

Ah, I see the M5 AtomS3 Lite has a grove, which is probably robust enough for me.

Great!