@Jo.so.jo Your last paragraph leads me to think that you may have Broadband boost. This is a package which includes 'wifi guarantee' amongst amongst things, where you can receive boosters if your coverage is poor. But the wifi guarantee with Boost is only 3mbps in every room.
More significantly this would mean that you have the black Hub 4.2?
This is only a Wifi 5 router and not capable of anywhere near gigabit speeds.
If you have Sky Q with the hub 4.2 then this will add a further wifi bottleneck as the mini boxes for instances are only capable of around 150 Mbps over wifi.
If wanted to use your own router then you need to look for one which supports DHCP option 61, and there is a little config you have to do which means they are not ideal for anyone who isnt tech savvy.
