I installed Oracle_VM_VirtualBox_Extension_Pack-6.1.18.vbox-extpack and enabled USB 3. When I booted the VM it took over the USB-C port and I lost all network connection on the host. yum update in the VM still failed.
So my suspicion of the USB Ethernet adapter was correct.
BTW the Laptop has 1xHDMI, 2xUSB3, 1xUSB-C and a micro SD card reader.