All of my cars have Gtechniq ceramic coatings (five year). I had them applied by Byron and his team at https://www.topwrapz.com/ in Nechells, Birmingham who I’d highly recommend. I mainly use products from https://bilthamber.com/ (Touch-Less, Auto-Wash, Auto-QD etc.) but I’ve used those long before having my cars coated. I don’t think you’ll enhance or restore the coating yourself. Mine are supposed to go back to Byron once a year for a maintenance wash and check to keep the warranty on the coating then I think he may top up any panels that seem like they need it. You’d probably be best to find out what brand of coating was used and find an accredited detailer for that manufacturer. Take it to them occasionally for maintenance washes and seek advice on products specific to that coating. Auto-QD seems to help the finish look that little bit better after a wash and something like Autoglym Extra Gloss Protection might give the colour a deeper shine but it shouldn’t be necessary - I haven’t used it since before my cars were coated.
We have a Nissan Qashqai which we bought when it was 18 months old. Noticed a small sticker on the windscreen showing that the original owner had had it treated with Supagard’s Bionic Technology ceramic coating. It’s now six years old and all I’ve ever done is wash it with a cheapie Halfords shampoo that I’ve had for years and then rinse and dry with a microfibre towel. Always comes up with a good shine and I’ve never felt the need to polish it.
Would be good to know what product was applied as the company may have a product which benefits it ie a quick detailer.
A good decon shampoo once every 6 months can be a good idea to bring the coating back to life, Garage Therapy do a very good one.