The rumor of the 19mm PCE was about two years before it actually came...
So ...
this type of lenses is for pro... a pro (in architecture) needs a bunch of lenses... the 24 PC-E isn't good enough... especially with a D850.
19 + 45 + 85... we need a lens between the 19 and the 45... 24 or 28 or 35... but a lens !
meanwhile, as a nikon shooter... for architecture i keep my arca RM3D... for PC, canon offering is much better now, even if the 19 PC-E is superior to their 17...