Optimum Ubee modem router access

The Optimum Online upgrade to 500 Internet uses a Ubee combo modem-router that does not allow access to basic router settings. Even though the service tech was able to configure it, customer service is not able to make changes either.
When I requested what to do if I perform a Factory Reset, they avoid answering the question.
Does anyone have a suggestion?
I have a list of compatible modems if necessary to go with a separate modem. Does it matter whether it is DOCSIS 3.0 or 3.1?
As a last resort, I will go ahead and change to Verizon.
Has anyone successfully resolved this issue?