Not at all. Just make sure they deliver Cat5e/6 from the ONT to the router and NOT Coax.
I have Verizon FiOS and the set-top boxes need internet access via their coax aka MoCA, so you will likely do what I did: Use their router for that bridge functionality. I've put mine into a DMZ of the router, and it knows NOTHING about my network otherwise. Not used for wifi or any other functionality. The IP addresses its DHCP gives out are on another subnet. In short, It thinks its at the gateway, and it knows nothing about my network's existence, thus making the security of this device the provider's problem. I can't even access it easily because as far as it is concerned, my network is on internet-facing side from it.