External usb works fine, and I can establish WiFi connections to the Internet.
Any way, the suggested solution here ([Networking basics on qubes - #3 by unman]) doesn’t work. Maybe some details are still missing…(!?)
Another side effect using sys-usb is that the touchpad does not work, even after applying the solution indicated here ([Mouse and tablet can't click-and-drag using sys-usb · Issue #6453 · QubesOS/qubes-issues · GitHub]), it’s not possible resize or move any window, even if the mouse can be moved, and clicking works as well.