That should not be a problem. Did you try a different USB port? Does your HDD need an additional power supply? Or does the format change? What's the capacity? And better confirm the model number,...

I don't really think it's easy to fake a label. But it can't be find on the device manager and anywhere.

their newer version only supports Qos not bandwidth control

It can't be done like that. Will cause broadcast strom

As long as you can get a public IP from the sim card provider, you can open ports for your DVR so taht you can view the cameras outside

I think you can check the firmware and hardware version and look for a update.