@CLS while speed to the hub can be greater when you get full fibre thst does not mean Wi`Fi speeds improve as they are affected by the layout and type of construction of your home. Doorbells are often an issue as they are often fixed on the outside of a double thickness outside wall. One issue with getting full fibre is often the hub is moved which can cause previous msrginal connections to fail. If that applies you coukd try buying a longer ethernet cable to connectvthe hub to the ONT so the hub is out in the open on a surface above obstructions like radiators.
Otherwuse you may need a wifi extender.
=========================================================
65inch Sky Glass, 3 Sky Streaming Pucks, Sky Ultrafast + and Sky SR213(white Wifi Max hub) main Wifi from 3 TP-Link Deco M4 units in access point mode
