The router colleagues CANNOT connect to the optical fiber. You must have a fiber optic modem. A colleague from the operator will get it. It will probably also be equipped with a router (Funbox), if a colleague has a TV from Orange, it will be even difficult for a colleague to replace the operator's device with any other (but of course it will not be impossible). Added after 1 [minutes]:
Do you have any solution with me?
wait patiently for what you get from Orange, because now you can speculate and theorize.
You will get a nice funbox, you will see what the range will look like. If it is too weak, you will put your router in another part of the house, or you will turn off WiFi in the operator's device (if it is possible) and, after appropriate configuration, connect your router next to the operator's device.