1 gig over wifi is only possible with a high spec wifi6 router AND a wifi6 enabled device.
They are providing you a 1 gig service, however they could make it clearer IMO as you are not the first person to question this.
They are bringing out a hub5 that is in 'testing' right now, it is a wifi6 router. But its laced with bugs and shows no sign of being fixed.
Get your our own wifi6 router and put the hub4 in modem mode, remember the read the small print in future.