Hallo,
today I got hyperion.ng to work on my rpi4 with SK6812 LEDs in pwm mode.
(The sk6812spi mode does not support my 264 LEDs...)
To use the pwm mode I've to set dtparam=audio=on in /boot/config.txt.
With this setting I deactivate audio and hence the audio output to the HDMI interface, so kodi has no audio output anymore.
Is there any solution to get back the audio output with the pwm mode.