Some of you may recall that I had reported music interruptions/hard crashes/random restarts when using portable DACs with my Macs, regardless of whether they were being used as core or endpoints. This could be seen in Console information, where several errors linked to various Core Audio processes would be listed right before the crash/random restart occurred.
After doing a bit of troubleshooting myself, I have finally found the culprit, and hope this information may be useful to others facing the same issue.
Initially I thought this was due to a DAC hardware fault, or to a clear incompatibility between those DACs and Macs, as crashes were happening across different machines with different Mac OS versions (such as Mojave and Catalina). Later I thought this could be due to incompatibility with other audio software/extensions on the Mac; but since one of the Macs has just a bare bones OS installation (the Mac mini used as core), I had to rule out that possibility.
Well, it turns out that the problem ONLY occurs when activating Integer Mode on any audiophile software (in my case, Roon and Audirvana) - due to the deprecation/gimped implementation, by Apple, of Integer Mode in newer Mac OS versions (particularly from Mojave onwards), such a mode cannot be relied upon anymore. My guess is that, when Integer Mode is used on newer OSs versions, this also deactivates certain mandatory elements of Core Audio, thus causing various crashes.
So after turning Integer Mode off on both Roon and Audirvana, the problem magically disappeared and I can finally use my portable DAC without any crashes/interruptions. Again, I hope this can help others potentially facing the same issue!