When you said Maxis Huawei router, I presumed its those 4G Broadband router...

Maxis 4G are all running on Private IP Address that was assigned by Maxis own DHCP server.

Unless you are corporate/business account, you will have the chances of getting a Public IP Address but depending on the availability, you might get IPv6 instead of IPv4.

You can login to the router & check the WAN connection is using which IP Address then open a browser & Google for "Whatismyip" & make a comparison of both IP addresses. If both matches then you are in luck... that's the Public IP address.

If both doesn't match then you are using Private IP address instead & you must contact Maxis to request for a Public IP.

Not all Maxis 4G router have the capability to configure the DDNS inside the router or support the DDNS service you wanted to use, thus be prepare to install the update client in the computer instead. I've encountered a router that support the DDNS service but somehow the DDNS provider's server are not updated due to unsupported router model.

Hope this clarify & help.