@xxjennxx apart from fitting a time switch to the hub's power supply there is no simple way to switch wifi off other than manually but of course kids can switch to use mobile data. You could program a firewall rule to block the IP addresses of their phones between certain hours but most teenagers can get round that in a few seconds.
You may want to compllain to Sky thst they stopped Broadband Buddy before having a replacement avaiable its something that the Superuser group has raised with our contacts an How to make a Sky complaint | Sky Help | Sky.com
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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
