That's why you have them run CAT5 from the ONT into your house. The wire is usually there already, since they install it "just in case" you get phone service (apparently it hooks into the CAT5 port on the ONT. If you have home phone service, you have to use coax for internet since ethernet is then used for phone). Then you can use your own router (in my case a VM running Vyos). We have FiOS TV as well, so I have a device acting as a MOCA bridge (on it's own VLAN, I want their stuff isolated from my home network) and their devices connect to that via coax. You just need to make sure you forward the correct ports to the right set top box so you get the TV Guide and other features. If you have a DVR, then that's the device that everything is forwarded to, and it shares the information with any other set top boxes it sees.