Being in the same camp as you and not letting the dealer touch mine when it was new, they do tend to come pretty dusty. You don't say what colour you've ordered, but if it's a dark colour, you might find it needs a little fettling before you apply any protection, obviously depending on how permanent a protection you want to add. Mine needed a fair bit of machine polishing to remove transportation marks, and general issues from the paint. The bonnet was the worse, because they use an elasticated material to protect it during transport, but this actually marks the paint. Luckily I use a machine polisher every day and have for 12 years with my own work, so I didn't have any problems, but if you haven't got experience and it is a dark colour, I'd strongly advise you use someone in your area that knows what they are doing. Machine polishing is not as easy as some would have you think, and holograms are easy to get on the surfaces, a nightmare to remove, and will drive you nuts once the sun comes out.
As for sealing the paintwork, I've tested most products through my business, but I don't work with painted surfaces, so I cannot profess to be the fountain of all knowledge with this, but I've had amazing results from the new improved Autoglym HD wax as a finishing product on my own Black T6, which is possibly the hardest colour to maintain. (Silver and Grey being easiest)
Some rave about ceramic products, I personally didn't find they stood up to other similar protections, but it's a personal choice.
Oh and bare in mind that any protection you add or pay to have added, is only as good as the aftercare. If you spend daft money on a 'magic' coating, then take your van to a local carwash gang, or even let the dealer wash it during a service, then you might find you've wasted your money. I'm an advocate of using businesses that know exactly what they are doing, but shop around. There's a big flash, glass fronted, leather sofa, Nespresso serving business near me that will happily take up to £1000 from you to apply a ceramic coating to your T6, and they are not short of mugs with expensive cars lining up to pay it. There's also some very experienced mobile detailers that will do exactly the same job for a fraction of the price, and give you better, more realistic aftercare advice.
