I am tenacious I wanted to get back on the test
now works
I have disabled all UDEV rules
and I just did:
"stop pulseaudio.socket"
this is what creates the problem with libusb as well
the only drawback is that qemu remains frozen
once the usb-audio is recognized
if instead I remove the usb-audio stick everything works again
and is perfectly recognized with:
usbaudio.class and hid.class as in "real hardware"

here the video with the test:
https://www.youtube.com/watch?v=nH1_b3gwxc0

I hope it will be useful for qemu and add any improvements