This router works with any modem.
Just make sure what kind of technology is offered from Frontier. I believe they use cable so you will need to buy a Cable modem and you will be ready to connect this router to your Modem.
Remember this Netgear AX-12 is just a Router not a Modem/Router.
You can enjoy the real full experience of the WiFi 6 is you have devices with WiFi 6, other than that you will only have the speed offered for the oldest technologies.
Is a great router, stable and easy to use. Great signal and capable to perform up to 8 devices on 4K streaming at the same time without buffering. Your ISP speed is really important. I think Frontier only offers speeds up to 45Mbps, not enough for smooth 4K streaming. Anyrouter will hesitate with speeds under 300Mbps for the today's demands