The GL-AR300M routers only have 2.4GHz 802.11b/g/n wifi, which is much slower than 5GHz 802.11ac wifi that your smartphone would have. Also, they only have 10/100Mbps Ethernet ports, so your modem connection is limited to maximum 100Mbps. These inexpensive routers do not have powerful processors.

I have a GL-AR300M16-Ext and do not even get 70Mbps over wifi, given the congestion on the 2.4GHz band in my area.

I do not work for and I am not directly associated with GL.iNet