A minimal Micropython script for playing a WAV file using I2S with an ESP32C3 and MAX98357A.
Lots of sample WAV files can be found here.
Also added i2s_wav_file_from_http_get.py which gets the wav file from a http server (I used busybox). You can play a wav file of any size as data is read 1Kbyte at a time from the http server. I may experiment with lighttpd to see if I can have the http server convert from mp3 to wav on-the-fly.
