There's not a great deal you can do with quartz once it's lost it's sheen.
Despite having a very similar production line to granite and marble once the slab has been formed, it's just not possible to re polish quartz in situ.
I did have a couple of customers who claimed to be able to take scratches out of Quartz (which is extremely difficult) and both explained the process had more in common with polishing car body paintwork than anything in the stone industry but they never expanded beyond that.
It's pointless putting any form of sealer on the quartz, it simply wouldn't soak in as the resin holding together all the quartz and glass chipping is chemically impermeable.
So the option that leaves is a top dressing, similar to the sort of thing that would be applied to Amtico. But that would be high maintenance indeed.
Have a chat with
Tile HQ see if they suggest anything. It's their product and not branded.