Need help with revealing ethernet/phone cables at home (UK)

I have a 1 Gbps fiber internet connection provided by YouFibre. The ONT is mounted on an exterior wall and connected via a fiber cable through a drilled hole. I’d like to move both the ONT and the router to the living room, and if possible, make use of the existing wall sockets, as I plan to install PoE CCTV cameras. However, I’m confused about the wiring and sockets in the house. There’s a Cat8 cable running under the carpet, and when I lifted it, it appeared to go toward the center of the living room. Based on my research, the Master Socket 5C is not used for fiber internet connections. I’m wondering how I can utilize the wall sockets in this setup.

Bedroom (upstairs)

Living room downstairs

Living room(downstairs)

Room 2 (Upstairs)