Have a AV7701 and its fine, but I also have a UMC-1 at my office and have never used it for home theater. Seems like the UMC-1 did not have such rave reviews based on it's firmware issues and glitches, but in stereo duty I have enjoyed its sound quality. Would rewiring for a UMC-1 be a worthwhile endeavor for my home theater?
Note I only run my Oppo 103 to my AV7701 as the AV7701 does not do 4k/HDR pass through, so I would approach video the same way with the UMC-1. Optical from the TV for Smart TV, HDMI audio from Sony X800 and video straight to TV, and the 103 via HDMI for both video and audio. Mostly TV watching, some movies, some music (mostly audio files from drive via 103 or Pandora, CD, DVD-A, SACD via 103 as well).