I use two TRS cables into my motu interface which allows me to have pairs of inputs as stereo or dual mono inputs, if I choose stereo pair they always panned properly (by the audio interface) and I can use single stereo track in DAW and if I use dual mono I need to have two tracks and I need to hard pan both left/right.
this worked for me also with mono TS patch cables but they were short, I switched to TRS when I needed more length and all I have longer is TRS cables.
I can’t hear any significant difference in audio between this, headphones or using OB, they all have different gain but if you gain match the outputs they should sound the same.
I suppose that with the audio interface there’s also a factor of the ADC conversion and the preamps that can slightly alter the sound compared to what’s coming out of the DN, but it shouldn’t be something significant…