During the press briefing of the new Z50II camera, Nikon confirmed that they had removed the space from all of the Z camera models:
Z9
Z8
Z7II
Z6III
Z6II
Z5
Z50
Z50II
Z30
Zfc
Zf
Some of the Nikon websites have already been updated with the new nomenclature. Here is how this page looked a few months ago: