USB to coaxial all-digital converter circuit - what's required?

Background: I want to use my MiniDSP 2x4 to perform EQ duties, but I don't want to use its DAC. I want to take the digital signal from the USB output jack and turn it into either coaxial SPDIF or balanced AES/EBU (could also do optical I suppose).

Does this require a specialized IC? I don't totally understand the differences in format across the different cable types.

I know I could order one for cheap, but I thought it would be a fun project to build the converter myself.
 
I want to take the digital signal from the USB output jack and turn it into .... SPDIF ....Does this require a specialized IC?
There're professional grade chips like DIT4192 to output the S/PDIF provided you manage to decode the USB audio, I'm assuming you need only two channel stereo.

could also do optical I suppose.
Yes, easily and I think the following might help.

https://en.everlight.com/wp-content/uploads/2021/02/Application-of-PLT-and-PLR-on-SPDIF-V1.0EN.pdf