It aint childish, It;s basic telecom wiring.
We can all wave willies about lightning protection, wideband carriers, party lines or digital carriers or earth calling signalling.. None of which are a problem to the op.
The Op has simple split pairs.
If the OP follows the colour codes as prescribed in all sockets and junctions boxes he won't have split pairs which the OP has now. If the Op has problems with his party line I'm sure we will all be able to advise.
Banded cable = solid cable = socket
Blue/white = Blue = Terminal 2
White/Blue = Orange = Terminal 5
Orange/White = Green = Terminal 3.
Simply wire as above in all sockets and junction boxes and all will be well. Any apprentice telecom engineer could see the same. The photos clearly show that the OP does not have wiring as prescribed above and has split pairs. Split pairs are bad for broadband.