I guess because their customers, in our case 3f, want their HLM properties built as cheaply as possible. Everything about the building is cheap. All the electrics and pipes are exposed, I imagine it costs more to bury them in the walls. There were only 9 plug sockets in the whole flat when we first moved here although a few more have been added. Until last year the boiler was the original from 1965. They even skimped on the head height in the cellars/garages so that anyone taller than about 5ft 8ins has to duck.
OK, I was going to suggest that was the sensible thing to do, it does mean that you could re-connect the house extensions (to the phone port on the livebox) if you wish - and have not done so already, of course.
I guess the important point is that if the set-up works for you, and you are happy then the advice that you received was good. I note that they have 2x2 MIMO, not sure if they have beam steering but either way very possible to be better than the Wi-Fi in the Livebox.
I don’t use the Livebox Wi-Fi either - it’s in a corner of the house so not a great position, so the actual set up is similar to yours. At some point I’ll “do the network right” which will involve running Ethernet between some of the rooms.
We get to hear every tinkle and plop (well I do, hubby’s deaf as a post!) but only if it’s very quiet so usually at night.
A few years ago we had a single lady living upstairs and after a few months she got a boyfriend. The politest thing I can say about the weeks that followed was that she had a noisy bed, she was very “expressive” and he had considerable stamina!!
Happily, she moved in with him fairly quickly.
The current resident spent the first 18 months crying loudly every single day because she had been dumped by her boyfriend. Poor woman was seriously depressed. She got a cat last year and the crying has turned into baby talk. Ah!!! I’m happy she is happier but I’m also happy that the incessant wailing has stopped. I’m ashamed to say that my sympathy wore thin at times.