Hello!
I can confirm that the content is current and jetson-io is designed to use overlays to alter the pin configuration. This is how jetson-io has always worked. Please let me know if there is something that I am misunderstanding.
That looks correct and yes by default this should drive I2S4. Are you able to probe the I2S signals to see that they are being driven? If they are being driven then it is worth checking that the sample size and sample rate being outputted are compatible with the codec. I noticed that you did not specify the sample size or sample rate in the speaker-test command and so it is not clear what these are defaulting to. Hence you may wish to try …
speaker-test -r 48000 -F S16_LE -c 2 -twav -D plughw:CARD=tegrasndt210ref,DEV=0
I could not find much information on the ES9023 DAC but at least the PCM5102 DAC looks like it should work. In fact another user has used the PCM5102 DAC successfully with other Jetson platforms in the past.
Regards,
Jon