AAC 7.1/LPCM Passthrough Not Working (Plex on Chromecast with Google TV > Samsung S90C > Samsung Q990C)

[HAMCORE]

Hello!

I am having troubles passing though AAC 7.1 audio (which should convert to LPCM) to my Samsung Q990C 11.1.4ch soundbar. I have "Passthrough: HDMI" on for PLEX, "Auto" sound output on Chromecast with Google TV, audio output set to passthrough on Samsung S90C TV, and the Q990C soundbar connected via eARC.

I tried plugging it directly into the soundbar. Initially with all sound formats but DTS selected on the Chromecast, it did not work. However when I switched to "auto" formats, the bar was able to play MULTI CHANNEL PCM/LPCM.

I can play Dolby Atmos TrueHD 7.1 just fine, but somewhere my AAC audio is converted to STEREO PCM instead of LPCM.

I tried searching Reddit and Google for about an hour and couldn't figure it out

[Svet]

Not exactly the same but I was convinced that my s90c did not passthrought to the soundbar in DTS. This morning, when connecting a BD player for the first time it did.

Switching it off again...back to the problems.

Despite all the good things about this TV, in terms of audio it is unbearable.