internal Router Options?

How do I access my router settings on my modem. The normal way via web portal says to use the app. The app has no settings. If this is really the only options available, ie cannot set DMZ, cannot set bridge mode to you your own router, network mapping and all that jazz, I will be going back to vzw internet. Their modem has a full router built in that let's you fully customize your internet.

And if infact there is no way to change any of this, you need to warn people saying:

Your server projects for school will fail

Your games will run like crap and may not even work due to network mapping.

Multiplayer games will run very very badly and party functions won't work