Based on this output, I think you'd need to set in EmulationStation the Audio Card to Device.

To get the name of the mixer (volume control), run

amixer scontrols -c Device

and choose the 1st entry and set it as Audio Device. For instance, in my case, the USB audio card is named 'Controller':

amixer scontrols -c Controller Simple mixer control 'PCM',0 Simple mixer control 'Headset',0

I would use PCM as the AudioDevice settings in ~/.emulationstation/es_settings.cfg:

This should fix the audio not working (or the volume slider rather) in EmulationStation.

For Amiberry, I'm not sure why it's not working - maybe it's trying to use the 'default' card and it's not working ?

Try following the advice here and create a /home/pi/.asoundrc file containing

defaults.pcm.!card 1 defaults.ctl.!card 1

Per-emulator video mode switching not working on Pi400 and 4.7