Which Z DX lenses did you have in mind?
At least the 16-50mm DX is very small.
I agree with Hugh so I'll answer these two questions:
First the lenses don't have to be pancake lenses but they should not be FX size lenses. They should be proportional in size to the cameras they are designed for. There is no 35mm, 28mm or 24mm f/1.8 or f/2.0 lens in Nikon's Z DX line up and there should be. The Nikon 28mm f/2.8 NIKKOR Z Lens (SE) is a reasonable size but f/2.8 is far too slow and there is no need for it to cover FX if it is intended for use on a Nikon Z DX body.
The Nikon NIKKOR Z DX 16-50mm f/3.5-6.3 VR Lens is smaller than it needs to be. It's OK as a low cost kit lens but f/6.3 is ridiculously slow for me. A better quality build 16-50mm f/3.5-4.5 would be a start but a 16-50mm f/4.0 would be what I would find reasonable.
If Nikon is serious about Z DX then there should be a high quality 16-55mm f/4.0 and f/2.8 zoom and it's size should be proportional to the Z50 and Z fc not to the Z7 II or Z6 II.
Here is a list of Z DX lenses for sale at B&H Photo today, 2021-09-09:
Nikon NIKKOR Z DX 16-50mm f/3.5-6.3 VR Lens
Nikon NIKKOR Z DX 18-140mm f/3.5-6.3 VR Lens
Nikon NIKKOR Z DX 50-250mm f/4.5-6.3 VR Lens
They all have a maximum aperture of f/6.3 at the long zoom setting so NO sale! I believe they all have plastic rear bayonets so again NO sale!
I've mentioned the AF-D 28-70/3.5-4.5 Nikkor many times and noted that it is suitable for a D850. I've mentioned that it gives "decent" images wide open but if at all possible I stop down to f/6.3 to f/8.0. If I stop down an f/6.3 lens one stop I'm at f/9.0. That is ridiculous and about as far as I'm willing to stop down a lens on DX except maybe f/11 for macro. An f/6.3 maximum aperture lens is TOTALLY unacceptable for low light photography.
I would probably buy a Nikon Z fc if it had two function buttons on the front and I could buy quality Z DX lens or two that is proportional to the body. Given the Z fc's size and price point I've come to accept no IBIS. The lack of two function buttons on the face of the Z fc makes the camera unacceptable to me for casual guest events photography.
Again No plastic rear bayonet! I will not buy a lens with one! Even my 75-150/3.5 Nikon Series-E zoom had a chromed, bronze bayonet.
I'm not interested in collecting vintage rangefinder lenses (for myself) to use on a modern Nikon Z mount mirrorless camera. I find reading about them interesting and seeing photos of the cameras and lenses but I'm not a buyer.
I want quality Z DX lenses that are proportional to Nikon Z DX bodies or I'm not a buyer.
Dave
All typographical errors and loose logic is expressly intended!