Many people using Stadia on their TV via Chromecast Ultra have problems with A/V sync.
In a lot of occasions this is due to the 5.1 PCM audio on Stadia that only the latest TV's with eARC can forward/passthrough to external audio systems (in case no A/V receiver is used). In all other cases, the TV has to convert the 5.1 audio to stereo PCM before outputting it e.g. to a soundbar. This results in additional audio processing and perceivable audio delay that cannot be fixed.
There is an option to enable/disable HDR in the Stadia app. There is an option to limit the output to 1080p with balanced settings.
Why is there no option yet to switch between stereo or 5.1 audio?
The automatic EDID detection is cool, but it only tells the Chromecast Ultra that my TV is able to accept 5.1 PCM, not that I'm actually able to listen to it with internal or external speakers without delay!
I think the ultimate goal should be that they support passing through and/or transcoding and muxing the audio stream to DD+. I personally don't have an issue with it as I use an AVR but I can see this being really frustrating for sound bar users.