You might consider finding an Oppo 203 or 205. The 205 measures as well as the OktoDAC, so use that instead.
THe cost is obscene, but might save you much frustration and configuration hell.
Since I already had a 103, I chose to prioritize for audio quality in the PC/Multichannel (JRiver) -> OktoDAC, and 'suffer' lower quality for streaming content thusly:
Streamer (hdmi) -> Oppo103(analog out) -> MotuUSB ADC (usb out) -> PC USB input => (JRiver)....
It works, but came with a good bit of 'twitchiness' in the setup/configuration, and still occasionally forgets who it is (JRiver, mostly).
But, I have weekly movie nights with friends, and aside from the occcasional cussing after a 'suprise' Win10 software upgrade and subsequent 'loss of USB recognition', it works extremely well, and they are simply astounded by the "Big Sound".
(Oh, and for movies, I split the HDMI out from the streamer using the Oppo, and send that wirelessly to a projector.)
> The 103/MotuADC combo robs me of a good bit of SN/Dynamic range, but frankly I don't miss it.
> I already had the 103, and the MotuUSB ADC was cheap....so the total cost was small, and this approach retains super high quality audio for PC based sources (ie, direct to OktoDAC from PC).
>The Oppo HDMI surround to analog conversion does NOT give you ATMOS decoding, so there's that tho.
Still, if I were starting from scratch, I'd be mightily tempted to just invest in an Oppo 205, or even a 203....esp if the OktoDAC is that expensive now.
Consider the 'time cost of money' - a potential big savings in effort and annoyance for you, since you already understand the Oppo user interface and abilities.
Or just accept defeat and invest in a 'lower quality' but affordable AVR..which might get you Atmos surround as well.
Best wishes!!