Hi enmus, and thanks for your input.
I created a new qube sys-usb3 and set to PV mode.
Assigned usb 3.0 controller to it
qvm-pci attach -v --persistent --option no-strict-reset=true sys-usb3 dom0:00_14.0
sys-usb3 qube starts without issue.
Inserting a USB Block device to any of the three USB 3.0 ports makes it available to the Qubes Devices widge.
Assigning a usb block device to my untrusted domain makes the device available but READ ONLY to the untrusted Files app.
dom0:00_14.0 is USB 3.0, assigned to sys-usb3 qube with PV mode.
dom0:00_1a.0 is the laptops webcam, assigned to sys-usb standard qube.
dom0:00_1d.0 function is as yet unidentified. If I attach it to sys-usb the webcam becomes unavailable. So I attached it to sys-usb3 and it appears in the Qubes Devices widget as sys-usb3:1-1.6 - 8087_07da I think it might be for the SD card port. I’ll test that as soon as I get my hands on an SD card.