The good news is that many devices that require drivers on windows work without separate drivers on linux systems (the drivers are built into the kernel and/or ALSA). However, the bad news is that if your device doesn't "just work" most vendors don't bother making drivers for linux systems so that may be the end of the road.
It will really depend on what kind of kernel the QNAP is running, what the ALSA support looks like, and whether your device has good linux support. The DAC 2 claims to be UAC2 compliant, which means it would likely to work without a driver on a normal desktop Linux system. Depending on the QNAP's environment it may "just work"