HDMI 10" and 8" IPS LCD Screen - No Audio?

Like another user here, I’m using the pimoroni 8" LCD kit that is advertised to have digital audio out. I purchased the recommended I2s audio amp (Adafruit I2S 3W Class D Amplifier Breakout - MAX98357A) and wired it up as such:

LCK  -> LRC     Left/Right clock
BCK  -> BCLK    Bit-clock
DATA -> DIN     Data
N/A  -> GAIN    Check the amp datasheet/docs for this pin
N/A  -> SD      This is the ShutDown pin to disable the amp
5V   -> Vin

And I got nothing. I went back and forth via email with a rep from pimoroni and their conclusion was that they didnt really know what was going on and that they would only offer to replace the driver board.

Whats more frustrating is that Pimoroni tweeted a video of the digital audio seemingly working with a pirate radio board: https://twitter.com/pimoroni/status/1017713464951955461
So im just not sure whats going on. Some documentation would be great.

Background to my project: I’m using this HDMI board to act as a small monitor for my Retrotink 2X. The video comes through fine. Just no audio.

Anyone used this screen before outside of a picade project or without a pi, or has insight on how the audio output works? Info would be greatly appreciated.