There are two issues here:
1) You generally can not use 4G for the radio side. The reason is that a consumer LTE service will not usually give you a
true public IP number, instead using internal IP numbers of the network's router. This means that the radio would not be
accessible from the outside using standard port forwards. One way around this is to pay extra or find a network
provider that will offer a true external IP address that you can route to. The other way around this would be to setup a
VPN to reach the radio's network.
2) I am not sure if this device even provides basic router type of functions. You must have a "real" router that allows you
to forward ports. I didn't take the time to download the manual, but it looks like it only provides simple connectivity, but
again I am not sure. Nevertheless, it won't work either way, due to point 1 above.
73,
Mitch DJ0QN / K7DX