re:degaussing - yes, it has one (I saw it when tech opened up my first [broken] 3080), and it seems to trigger on power-on after being off for "some time" (not sure how long)... and it's quite noisy on my set (brrannng)
re: sound handling - just discovered that audio1 input is active on my 3080 when using Oppo dvi->hdmi source, as well as when using svideo1 source
Also just discovered while calibrating with Avia that "Sharpness" control has no effect when using the hdmi input (and ota dtv?? need to test that)...
which is why I decided to temporarily connect the Oppo via svideo1/audio1, so I could adjust sharpness setting (for analog tv) and A/B the difference, and noticed I still had sound coming from the tv speakers when I A/B'd Oppo between HDMI and svideo1 source.
BTW, FWIW and FYI, Audio out jacks are also active when watching ota dtv, but I don't know if it's a prologic downmix.