I'm encountering a similar issue albeit my truck isn't sitting in Mexico.
I bought an "in transit" 2021 Trail Boss LT, built at the Mexico plant, that has been sitting in a rail yard in Mesquite,tx for the last 4+ weeks.
The dealer is unable to provide me with a date as to when this vehicle will actually arrive. This is an extremely frustrating situation.
Just to add a little extra fuel to my current level of dissatisfaction with this whole mess, this same dealer just received a Mexican built Trail Boss a couple of days ago sporting a much later build vin number than mine.
If anyone has any clues about this mess I would like to hear them.
Hope your truck starts moving your way soon.