I don't understand what you mean by hub dynamo, but what I can say is that when the Xtrom is charged via USB-C, I can operate a device with power via the 220V socket, but this is NOT possible via the two USB-A sockets while charging. I don't know if charging and discharging at the same time can damage the device.

i just tried it out. it really does not seem possible to charge devices via the usb ports at the same time while charging the powerbank. the instructions for use only state that it is not possible to use the 220v connection (which makes sense).