Should I sell my DAC

If I was you I'd keep the Oppo for SACD. (even from your public library)
And buy a V-90. I see open box quality on eBay for $225 delivered.
You might be surprised which sounds better. It's definitely form factor advantageous. So is a streamer over a laptop.

When I went to the dealer to hear a demo of the Bluesound Node 2i and really liked MQA.  The dealer suggest adding a ProJect S2 DAC connected by Audioquest Carbon coax cable.  When they did an A/B I chose the Bluesound played by itself.  I for some reason noticed a better sound with MQA.  However, I questioned myself and thought the dealer new more than I did.  However, by adding the ProJect DAC I lost the complete unfold of MQA.  When I hooked things up at home using the DAC I noticed my bass to be less pronounced.  It sounded thin.  I removed the DAC and thought the Bluesound Node 2i sounded better.  So, I ended up selling the ProJect Dac on the Audiogon website half the price I paid for it.  I wonder if a lot of have been sucked in to paying more with the thought of paying more means it sounds better.  Unfortunately, I learned the hard way and I will be more causious in the future.  The support at Bluesound was also exceptional.  I hope someday they will add video so I can watch the Tidal video concerts and play hi res through my system.

I have a benchmark DAC3 connected to Node 2i in my main listening room. I would not drive node2i on it's own as the DAC is below standard and does not sound good at all. 
For my office set up - I may just end up keeping the OPPO 105 player and use the USB DAC. Maybe have OPPO digital look at adding new capacitors and helping reclock/mod the unit. They are 20 mins drive from my house. 

Just go to Ebay and type in Oppo 105 LPM. Prices vary, I opted for one of the least expensive

Love my r2r DAC. Makes bad compressed audio sound great, and uncompressed sound extra great, and no fatigue.