Just like with anything, when you’re wondering about jitter... first get used to the sound of your system/gear as is. Then make a change and see if you hear any difference. If your DAC really does turn out to be "immune" to jitter... then changing USB cables (or whatever digital cable you’re using) should have no sonic impact. That’s an easy thing to test... just barrow a few alternate cables and swap. If you hear no difference at all, then that’s a coin in your "immune" jar. If you hear any difference at all, your DAC is not perfectly immune.
I’ll just say that I too had hoped that USB had finally found a way to defeat jitter by placing the master clock in the DAC and pulling packets etc. Well, at least with my DAC (Hegel HD30) USB cable swapping was clearly audible with a few cables I tried, and more dramatically, adding the PCT USBe in the path (between Aurender and DAC) has revolutionized the sound. A lot of marketing hype will throw out words like "immune" and perhaps your device is designed in such a way that it truly lives up to that claim. But even my Hegel DAC was supposed to be relatively unaffected by upstream jitter via USB given it’s design, and I’ve found that to be not the case at all.
p.s. I’m using the phrase "jitter" to broadly mean anything that allows the data to still arrive at the DAC uncorrupted, yet somehow the sound of D/A conversion is affected by other factors that are not digital in nature. Jitter (timing of the data) is most often discussed, but there are other non-digital variables as well such as noise. It’s entirely possible that what many of us hear and call "jitter" when changing cables and transports is really just changing the type of electrical/mechanical noise that gets sent along with the data to the DAC. Galvanic isolation is an example of a device that attempts to address this type of variable.
