I found the resolution for the issue in the topic start. After opening the Google Home app, go to SA30 settings and enable the dynamic range settings. The SA30 is listed again under Google Cast devices in Music Life and all other Google Cast enabled apps (e.g. mPlayer Lite, Plex, etc).
It seems after a SA30 device upgrade you have to apply the SA30 settings in Google Home app. Maybe this is information can be added to any relevant manual/instruction? Transitioned to closed.