Why did you want it in the first place, its a very old device?
Return the VR600 to the retailer, as its not suitable for your usage, unless you use it as a very expensive wireless access point.
I was told it’s better to use than the normal smart hub 2 as they’re dreadful apparently
You were told nonsense.
Draytek appear to do a number of G.Fast devices BUT they start at £200+.
Openreach are no longer providing G.Fast, and anyone renewing their contract will either be offered FTTP if available, or VDSL Fibre 2, up to 80Mbs.
If you bought it online just send it back.
Routers supporting GFast are very thin on the ground but I believe you could add a separate modem (MT992) from Ebay. No experience of these or GFast though, so you'd have to do your own research to see if buying one is a good idea. Unless someone here can confirm.
What exactly are you trying to achieve by replacing the SH2?