What happens if you split your internet cable?

Question

Computer networks

Is it possible to make two ends of the twisted-pair cable going to the house? To connect one to the computer, and the other to the router? (If you pull the cable from the router, more cable goes out)
What are the consequences?
Why doesn't the provider use this method?
Does it depend on whether the cable is 8 or 4?
Is it possible to do this without contacting the provider? (Without actions with the switch)
In this image, as I understand it, 8-wire, I didn’t find something with 4

Answer 1

1. 8 wires are needed for 1000Mb/s, but the standard allows using 4 wires for 100Mb/s operation.
2. Providers used to use it, but now with the advent of fiber and tariffs of 300 Mb / s, they prefer to lay it honestly
3. It depends, see point 1
4. It's not entirely clear what you want. If you connect two devices through one cable in the apartment, then no problem.
If you want the provider to give you two lines, then this is unlikely.
But these are all extremely dubious decisions.