I just upgraded from 350Mb to 1Gb, and got a Superhub4 (I usually run an AmplifiHD mesh but forget about that for now).
I get nothing close to 1Gb. It maxes out at around 300Mb. This is the same whether I run a cable (tried 3 cables now, 2 Cat5Es and a brand new Cat7), or whether I use wireless.
With my iPhone (12 Pro Max) right by the SH4 I get 300 max. My laptops (various) get 300 max, wired or wireless. If I plug the Amplifi kit in and put the SH4 in Modem mode, I still don't get anything above that.
Samknows site shows over 1000 to the hub, but it tends to top out at < 200, either on SH wifi, Amplifi wifi (sitting a couple of feet from them) or ethernet on the to-device side.
At the moment this is a waste of money, as I'm not getting any more than I used to get when I was on 350Mb.
I'm sorry to hear you're not receiving your expected speeds after upgrading to the Gig1 Fibre package, this is a strange one. I've found your account and all your signal levels appear fine and can't see anything from here that could be causing this.
I appreciate it's basic, but can you please try performing a factory reset on the Hub to see if this helps at all. Just to confirm, have you tried running wired speed tests on more than one device? I appreciate you said 'laptops' but just wanted to be sure.