@BobbieR first check the speed test result in the Service Checker of the My Sky app or website as Sky test the speed to the hub daily. Assuming thst is as it should be the issue is in your home network. Given that the older black Sky hub supports WiFi5 speeds and in practical use delivers around 650Mb/s it is unlikely it is the hub itself unless you example is faulty which is pretty unlikely.
WiFi is great technology when it works and a pain when it doesnt. The signal uses high frequency radio waves as a carrier so while you can be close to the hub if there is even a layer of metallic foil will block 100% of the direct signal, internal walls cause loss of power the thicker and drnservthe wall the more power that is lost. Therefore consider the relative position of the hub which should be off the floor out in the open on a surface. Assuming that is true there is a factor where you can be too close as the hub contains multiple aerials and you can get areas within a couple of feet where the signal from two aerials cancel out, move a bit sideways and things suddenly improve.. Move 10 feet away and these dead zones are no longer an issue. A useful tool is a WiFi analyzer app which you can use on an Android phone or windows laptop which shows WiFi strength in realtime as you move round your home. You need a signal higher than -70dBm (note the minus sign so -60dBm is higher) for a usable connection.
Sky hubs do not allow you to reserve bandwidth for certain devices so while playing Rooblox does not use much data if your son starts a download and you then place a call his download could hog all of your bandwidth. It is wise to schedule updtes for games when other family members dont need the connection for other tasks..
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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
