Need to know more than a brand and year. Need the model and trim level/options to even start having a conversation. Pac-Audio and Axxess are places to start for adapters that may be available.
An external DAC may be pointless if the signal path inside the factory radio goes through an ADC and DAC in order to process the signals (which it likely does).
I'd start by putting a few lossless audio file types on a USB and seeing what the stock radio can read, just so you can figure out what other options you have.
Unlikely the antenna connection is compatible, and even worse - they are awful. They are the worst sound quality of any car audio component. Hard no on FM modulator AUX inputs. Given that the OP wants to use an aftermarket DAC, they are looking for a high quality interface.