@Craigrum the term "good" covers multiple factors like speed (bandwidth), lag (latency) and stability (jitter) different activities nedd different ones of these. For example running a Teams session uses minimal speed (less than 10Mb/s) but requires decent lstency and low jitter to avoid buffering. Downloading a large file however requires good speed but is far less affected by the other two.
I assume you mean Sky Q boxes which do act as WiFi hotspots when connected to a black Sky hub is that right? If so these are comparatively old technology which wass great in 2016 when lsunched but less so today. However if it works for you great but it has limitations and a limited life span as Sky moves away from satellite broadcasting.
Sky sell a product called WiFi Max which comes with a new hub which stops the Q boxes acting as hoyspots but can be paired with upnto 3 pod extenders which works for some people but a lot depends on the layout of your home and how it is built. Older homes with solid internal walls are an issue.
There are numerous third party systems you can buy at price points from under £100 to over £2,00. You mention an out building which complicates things quite a bit. Given one solution does not fit everyone you would need to give more detail before forum members can help with recommendations.
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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
