Can't get my setup to work. Any ideas?

    Hi all...
    This is my setup: RPI4+LE12+HDMI AUDIO extractor/splitter with ARC support+SPDIF optical output to receiver/amplifier.

    In this setup the HDMI video FROM the extractor/splitter is connected to an ancient TV with HDMI-DVI adapter and the video is transformed just fine, however... if I connect this same setup with the same cables to a true HDMI monitor/TV - that is NO HDMI-DVI adapter (I have tested this on three devices) I get an option to select HDMI sound in the Kodi system audio menu and all works as it is intended, BUT if I connect ALL OF SAME THIS to the HDMI-DVI adapter - no such option AT ALL. I've been at it for five days now and I can't figure this out - how does LE know what happens AFTER the extractor/spliiter? Why doesn't simply send HDMI sound out to the splitter/extractor so that I could then send it to my amplifier via SPDIF optical???
    Any idea much appreciated. Thanks in advance.
    Also I get no "allow passthrough" option in the ADVANCED menu at all.

    Quote from kinner

    Why doesn't simply send HDMI sound out to the splitter/extractor so that I could then send it to my amplifier via SPDIF optical???

    "because" Kodi audio output capabilities are determined by EDID data read from HDMI, which presumably isn't replicated or passed correctly from the TV via DP to the splitter to the HDMI port on the RPi and thus Kodi doesn't see an audio device to use. Connect direct and EDID is present and correct .. and you get audio.

    Connect the RPi board direct to the TV, run "getedid create" to capture the EDID to file and force Linux to see it as always present, then connect everything back via the splitter again and it will probably work.

    https://wiki.libreelec.tv/configuration/edid