I'd just written a long reply, when the website decided it was time to login again and just ate the whole thing… damn it. So here's a hopefully short summary:
I have the same issue of muffled sound, missing crispness etc. Can totally spot the same character that's been bothering me in your tracks. I have no such trouble with my other external gear, be it analog or digital. All going to the same interface, some balanced, some unbalanced.
Output modules seem to have a big effect here. The three eurorack output modules I've tried so far, in order from good to not-so-good: Waldorf kb37, Intellijel Audio I/O 1U, Befaco Out v3. The sound issue was present on the kb37 as well, but to a far smaller degree than on the Befaco. As I have since sold my kb37 due to space constraints (and the Befaco cause I didn't like it), I cannot do any direct comparisons but the Intellijel seems to be somewhere in-between, though closer to the Waldorf. Unfortunately I didn't have the time, money or space to do a scientific comparison. Also, my DFAM, Neutron and 0-Coast seem to have a bit more clarity and punch when recorded directly through their 6.3mm outputs, than routed though eurorack mixer->out->interface. Whatever that's worth.
The cables might play a role, but I'm not really convinced yet. I've got mostly BlackMarket, Make Noise and Doepfer ones, so not complete trash, I'd hope. Maybe it's worth getting a handful of Cordial ones for a simple patch to compare…
What output module are you using @Exposure? Or are the mixers, the VCAs to blame? Something else?
I'm glad someone is mentioning this with an audio example as I couldn't really find anything useful regarding this topic so far.