So I have 200+Mbps service and seem to get that fine when connected via Ethernet cable. My biggest issue is that when trying to stream movies it's constantly buffering , even when nothing else is online. And the modem is only 12' away from the TV. I have tried on 2.4 g as well as the 5 g connections. I checked my wi-fi speed and it's around 75mbps download and 25 mbps upload. the modem has built in router for wi-fi, it from the cable company. So should I get one of those pricey whole home routers, will it make a difference? something like this?