Eazy-peazy. Ordered via my phone at 5:01am PT, Space Gray 11 Pro, 256gb, SIM free (why does anyone ever order the model specific to their carrier, unless it's the only one available? No reason to whatsoever, and can hurt resale value later). Paid via ApplePay to my Apple card. Interesting that a bunch of you weren't seeing an ApplePay option. 9/20 delivery date, zero drama.
Also, anyone using one of these trade-in programs or selling to Gazelle or their competitors, is losing a LOT of money for the convenience of doing so. XS's for instance on Ebay are bringing a LOT more money than Apple is offering, and since they're so easy and cheap to ship, it's a no-brainer option to move on from your old phone. Even after Ebay & PayPal commissions, you're still waaaay ahead.