I would describe HS=Y in the pre/pro as putting a spotlight on the musicians. I'm very used to HS=Y sound. Letting the Speakers upsample turns the spotlight off while musicians playing. It's subtle and could warrant more listening.

Different hardware ie 818v3 without MQA could be of different audiocharacter from my 861v8 since they are of different hardware and software versions and from the post-MQA era vs pre-MQA era.

Edit: OMG I think I just had a moment with spirit on the "Kyrie" 2L track @volume75. laugh

DSP8000SE, DSP7200SEHC, DSP5200SE sides, DSP7200SE rears, 861v8, 210, Sim2 Ultranero 4, Stewart Cinecurve 2.35:1, XEIT CM-5E Anamorphic lens, Dune HD Duo Cinema 8K and Wireworld Platinum 48G HDMI -> UHD722 -> Shunyata Omega Ethernet. Shunyata/Furutech power-cables/filters. SR Master Fuse@861v8. Uptone Etherregen with 10MHz OCXO clock.