If you are just asking if there would be an audible difference between fiber and cable to the house, I think the answer is no.
Once they provide fiber to the house into the ONT, will you be using the same RG6 within the house you had before, or will it be a new ethernet cable(s)? or fiber to the modem/router?
The difference in sound will be achieved by the last connection(s) before the streamer, or some have noticed differences by isolating the hifi with a fiber connection into their renderer.