Streaming services do use DD+ but some devices, like the Apple TV 4K, will output audio after converting to LPCM. Those devices will require more bandwidth than the ARC spec provides for multichannel signals.
Anyway, if the receiver here reports an Atmos/DD+ signal from the TV's apps, then Atmos metadata is present in the ARC signal. The 2080 does not support eARC. So, eARC Support should be turned OFF in the LG C1. Digital Sound Output should be set to Passthrough. Dolby signals will have Dolby Offset present and often require a volume bump compared to PCM signals.
Straight mode should be fine but Yamaha does recommend DSur mode for Dolby Atmos tracks with that unit. I'm a bit confused about the speaker layout and connected devices. While 5.4.4 was mentioned, I don't see any Presence Speakers or how they are configured in settings. Are they set as Height, Overhead or Dolby Enabled SP? Surround Speakers should be shown as SL and SR, not RL and RR when using five speakers at ear level instead of seven. I'd be interested in just how everything is connected and configured here.
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