Nikon Japan is already warning about Nikon Z6 III product shortages becuase of the high number of pre-orders:
In the past few years, pretty much every new camera has received a similar warning, even the new Pentax 17 half-frame film camera that is already in stock at WEX Photo.
Nikon Z6 III pre-order links:
Join the Nikon ℤ6 III Facebook Group