I had done the pre order stuff twice, once with Apple Pay selected for payment, and once with a credit card.
Same as last few years, tried the Apple Pay option first, and that failed. I use Apple Pay throughout the year without issue, but when trying to buy something direct from Apple, it invariably says nope.
Bailed and went back in and chose the credit card option, and went through no bother.
Done for the 15 PM but got the 25th as delivery. Stupidly never pre saved the item in the app, had to do a fresh order but literally took me 10 seconds, cost me 3 days.