@Jawini in many homes a single wifi router does not provide decent wifi in every room especially if you have more than 2 levels or its a home with solid walls like yours. The extra cost is for Sky's Wifi Max package which gives you a.newer router with fastercWifi and up to 3 extenders if one of their engineers agrees you need one to get a minimum of 25Mb/s in every room in the house. There is a chaper Broadband Boost bundle at £5 per month which will provide a booster if you need one but a lower guaranteedd speed of 3Mb/s. Many Sky customers have their Sky Q TV boxes which also act as. Wifi extenders.
Those are not your only option though you can buy third party wifi systems designed to give wifi through out the home. While boosters have their uses, with full fibre and its higher speeds, they rarely work that well far better are wifi mesh systems with faster back haul. Personally I use a 3 unit third party Wifi system from TP-Link that cost roughly £100 and gives me fast wifi (over 100Mb/s) in every room on 3 levels.
You also can buy a third party router system but not every whole home wifi system can be connected directly to the ONT.
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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
