Your easiest path is Roon.
Getting a DSP unit with DSP out is harder than you’d think and AFAIK this has to do with the need for a real CPU and driver to talk to it. The USB handshaking and protocol is complicated.
If you can forego the USB requirement, the miniDSP SHD is excellent.
https://www.minidsp.com/products/streaming-hd-series/shd-studio
Another choice is to stick with a PC source and use DSP capabilities of JRiver or MediaMonkey. You can even get DiracLive software that is PC based.