Cambridge dac?

Didn't mention this, but this player's dac is accessible and you can hook up a streamer. Maybe you already knew this?

Find a nice used Cambridge 851C  cd player. It has good dac chips in it which I believe are made by Analog Devices. The unit can be used as a preamp too, although limited for source connections. It should also have a good working remote to perform preamp functions. 

I haven't heard the Schiit monos, but I recently heard a $150K system fed by a 10 yr old $200 Cambridge 540c CD player, and it was one of the best systems I've ever heard. There is some magic in the dual Wolfson dac in these Cambridge, I would recommend the older DAC or CD player with the Wolfson chips rather than the new ESS. Affordable ESS dacs tend to be poorly implemented and lifeless sounding.

I’d go with the Gustard X16 over the Cambridge.  It also offers a remote if that matters — not sure if the 200M has one.  Best of luck. 

I have no experience with a DacMagic 200M, but I did try out a Schiit Modi Multibit. In the end I discovered that it sounded identical in my system to the tube output on my Maverick Audio TubeMagic D2 DAC that I had always preferred the solid state output on.  I opted to return the Schiit and then discovered that I could upgrade the three op amps in the Maverick Audio DAC with Sparkos Labs discrete op amps and that really stepped it up.

I'd recommend that you go that route in the $500 price point since it provides two output options.  If you're looking to get into a higher priced items, then my experience may not be worth anything to you.

Why not use a Schiit DAC? System matching and synergy has advantages.