@Vivi3
Unfortunately you still haven't listed the detected formats:
Highlight Settings/Audio/Digital output format = Auto (What formats are listed in the detected formats on the right when you HIGHLIGHT Auto?).
You also still haven't provided the brand/model of the TV (it matters since your TV is providing the decoding of any Dolby/DTS bitstreams since your 4660 is passthrough-only).
Also, even though you may have disabled the RokuOS "volume modes" (Options (*)/Volume mode = Off) , YT has a new "Stable Volume" setting that is enabled by default: During playback press Up/Up/Settings/Stable Volume = Off (unchecked).
Similarly Prime has volume modes as well: During playback press Down/Audio options/Dialogue boost = Off
Make sure volume modes are disabled in RokuOS, YT, and Prime, and check the TV's (brand/model unknown) audio settings in regards to decoding/transcoding/leveling/sync.