@Rod4 streaming video over wifi requires both sufficent bandwidth (10Mb/s for HD or 25Mb/s for UHD) but also low jitter. Jitter is the measure of regularity of the signal as if a data packet doesnt arrive in order the app has wait for it to be resent.
Few suggestions before spending money first is to make sure the device and the hub are out in the open so the signal is not blocked by furniture. Fire Sticks are a particular problem especially if the TV is wall mounted as the TV will block a lot of the signal as it contains metal. You can get short HDMI extenders moving the stick from behind the set which can help. Second is to restart your hub as it will then find the least congested wifi channel as a neighbour's wifi on the same or adjacent channel can cause interference.
However as many forum members have found a single Sky hub is not up to providing a fast and stable wifi signal required for streaming in every room in many homes. You can buy any number of whole home wifi solutions my own a set of 3Deco M4 units cost around £100 and gives rock steady UHD streaming. Alternatively you could buy Sky's own alternative https://www.sky.com/help/articles/sky-wifi-max losds of choice.
=========================================================
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
