Docsis 3.0 Router/Modem Advice

First off, let me say that I'm not the savviest person when it comes to network connections, but I am an avid PC gamer and have built multiple gaming computers in the past.

Currently I have a 15.0mbps Cable Internet connection through Suddenlink, and plan on upgrading to their fastest connection which requires a Docsis 3.0 modem where speeds are advertised up to 50-70mbps.

My current setup is a wired home network between 2 desktops. I have a Toshiba modem and D-Link EBR-2310 router. My internet works well when it actually works, but it seems that I suffer from frequent connection issues when trying to actively use both computers. Connection issues typically arise from me playing online games and my wife watching streaming Netflix or even sometimes from something simple as the both of us browsing the internet. The connection issue isn't only isolated to using 2 computers at once, I sometimes find myself staring at blank tabs and unloaded webpages while browsing the net.

From what I've read, the D-Link EBR-2310 router is most likely the culprit, as I've changed modems and even moved into a new house with little to no improvement.

That said, I plan on buying the Motorola SB6120 modem for the upgraded internet connection and have been considering purchasing a new router to ensure the best connection possible. Considering I don't plan on using a wireless network, would I be better off just buying the Motorola SBG6580 Cable Modem Gateway instead? I've read that it had wireless conenction issues, but considering I plan on using it solely for wired connections in a 2 computer home network, maybe this would be the best solution instead of buying an additional router?

Thanks in advance!