Hi,
I have tested the CXA80 with various sbc’s (PI 4, Odroid N2, Odroid C4, Nanopi Neo 3, Khadas VIM1). So far I have not seen any issues when the USB 2.0 compatibility setting (see manual) is activated, otherwise the CXA may not be detected, depending on the sbc used.
Note: switching off the amp will cause the usb audio device to disappear from volumio and show Alsa errors when playing or trying to play something. After amp power-on, the usb audio device will re-appear. No need to reboot volumio, just restart whatever you were playing or tried to.