Issue with Asus GT-AX11000 router

Hey

I am using the asus gt-ax11000 router with my netcomm NF18ACV modem from Orcon. So I'm meant to be getting over 800Mbps down and Over 400Mbps up. Once ive set the router up though i only get 170Mbps down and 340 Mbps up. My line test is fine when i run it through the router and if i go through the netcomm i get the speeds from the speedtest im meant to be getting.

Any help would be GREATLY appreciated