Though not HifiBerry Amp2 I have several units of DAC-amp combo for the Raspberry Pi series.
A Suptronics X400 v2.0 is used as you have described, with volumio, combined with my DIY speaker enclosures and DIY UV meter.
Another one, a Suptronics X400 v3.0, is fitted to this RPi3B+ Raspbian Stretch with Desktop unit, where I use this a my main desktop PC, for watching videos via Kodi and YouTube.
And another one is an iQAudio Digi-Amp+ fitted on a RPi3B Desktop unit.
So yes anybody can use the DAC-Amp combo as long as there are drivers available (better if those drivers are already built in to the OS, like in Raspbian).
I'd probably stay away from WM8960 based DAC-amps as those have no readily available drivers in the OS...
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"
Some people be like:
"Help me! Am drowning! But dont you dare touch me nor come near me!"