It's actually how CarPlay and AndroidAuto work. If possible they will use the available GPS antenna from the vehicle. This is why aftermarket radios that don't have built in NAV, but support CarPlay and AndroidAuto, come with GPS antennas.
1st, you won't lose you warranty for using a programmer to change tire size.
2nd, it's been posted on here that most dealerships are no longer doing programming for tire size. Your best bet is to contact your dealer and ask.
A dealer needs an allocation to order a vehicle, whether it be for inventory or a customer sale order. So either way, the vehicle needs to be built and then delivered and the timeline is essentially the same.
Some warranty. They couldn't even send you a return label? They at least did that much for me.
I hope they do right by you, but be prepared for the "used" headlight excuse or anything else they throw your way to limit your refund amount.
These 2 are popular on here. Do a search and you'll find several threads about them.