Long story, but I looked till I was exhausted for a max'd out 2021 - to no avail. Special orders were not possible due to things already discussed on this thread (like chips). I'm in Atlanta. I finally found one in Pittsburgh, but the truck was a 2020. Deep research revealed not much of a change to the 2021's at all. It was built in November of 2019.
I called the dealer in Pittsburgh in Oct of 2020, who told me they had performed a dealer trade to sent it to Ohio in Jan of 2021. The Ohio dealer in turn had just transferred it to a local dealer here in Atlanta. So it was driven from Pittsburgh to Ohio, then trailered to Atlanta. Biggest Qs were:
Why did it have 428 miles on it?
Why didn't it sell at either of the prior dealers?
I got some answers. The mileage was when it was driven to Ohio. It didn't sell because the Nav and other functions didn't work on the main screen, and all the techs at all the dealerships couldn't fix it. They certainly tried as noted in the service history.
I now owned a new truck, sold as a new truck although it was a 2020 and purchased in April of 2021.
However the Sync3 problem still existed. No display. I interviewed several service managers who were nice enough to hook me up with a Ford electronics tech that "floated" around to all the dealers here in Atlanta. He was supposedly real good at things like this, so I called him and arranged to have him look at the truck one morning. He hooked up his laptop, did diagnostics, and a few hours later viola! He re-synced the whole system and it worked. Updated all the firmwares while he was at it. Now I had a superior Expedition that was 100% up to spec. And everything worked.
I was willing to bend a tick by accepting a 2020, and everyone thinks it's a 2021. Since it was a new 2020, it was of course sold as a new car. The book values of a 2020 vs 2021 is only about $3,000 at this time, mostly due to the chip shortages. That figure will diverge with time, but I don't care; I've got the truck I wanted back in April (a black 4x4 KR with all options) and I couldn't be happier!
BTW - at last look this dealer was buying up a lot of expe's around the US and trailering them to this lot. I saw ~12 of them. Most were 2021's, a few Limiteds, a few XLs.