LG OLED evo C4 (eARC/ARC) + Apple TV 4K gen3 + Sonos ARC

...if you activate the eARC option on LG OLED evo C4 (2024 model) the native DD+ 5.1 audio is sent from the Apple TV 4K gen3 streaming apps to the Sonos ARC soundbar in Multichannel PCM 5.1 format with loss or little presence of surround effects and poorly reproduced central voice, while if you deactivate the eARC option on the TV (therefore keeping the less performing ARC transmission) the audio reproduced by Sonos ARC is the native DD+ 5.1 with the surround and central voice effects present and well reproduced...why does the Apple TV 4K gen3 in eARC mode transcode the DD+ 5.1 format into PCM multichannel 5.1 creating artifacts with worsening and decay of audio reproduction (rear surround and central voice less present)???...obviously using the smart TV apps downloaded from the LG store the audio in eARC passes to the Sonos ARC soundbar correctly and is faithfully reproduced in DD+ 5.1...is there anything that can be done to avoid disabling eARC (which results in the failure to play Dolby Atmos streams)???...has Apple support ever verified this strange behavior???...why isn't the "Passthrough" option simply inserted on the audio output of the Apple TV 4K gen3 avoiding any unnecessary transcoding???...