As others have mentioned these noises are completely normal. Upon shutdown if you sit in the truck it is waiting to figure out what is next as the fob is still in the cab. There is some sort of order of operations with the computer for shutdown that causes the clicks and whatnot.
I also own a '21 Explorer with the 2.3 and it does the exact same thing as my '21 Bronco with noises.
Back in 1983 there was a vehicle that was ahead of its time that continued to run even after you shut it off...
