Critical areas of an underexposed RAW

[AlexisMagni]

I don't see much noise in that photo.
In my opinion, if there's any, you can leave it. Especially if you don't reduce it with DxO.
Try doing a soft proof on PS matte paper, enlarging a dark or underexposed area. You'll see that there's not much to remove, even if it's a little noticeable.
So, out of curiosity, is the Zf a Bayer with or without a low-pass filter?

I will be printing that today on the Canon Pro Premium Matte Paper I have following your suggestion!

About AA on the Zf sensor, I have looked online, and it seems to be a mystery. Some people say a 24Mp Sensor must have, but a Nikon Rep told it doesnt. I honestly dont know. All I can say the Zf image is Soft, but not in a bad way. It doesnt look too sharp like a digital sensor often does, the tonalities are incredible, for Black & White included. I am not a Digital Camera guy, but the Zf is a homerun from Nikon

[robyferrero]

I agree with the Nikon representative. Even looking at the image, it seems like the low-pass filter is missing.
The low-pass filter gives the image a sharper appearance, but with a very slight blurring, like on a slightly blurred glass. It really seems like the image has a glass over it that creates "blur." I can't explain it better.
I personally don't like Bayer AAA filters.
I prefer X-Trans for this reason too.
You talk about sensors being too sharp, but the CCD is a sight to behold.
Then perhaps there's no such thing as a sensor that's too sharp; digital is intrinsically blurry.
I think a sharpness mask, even a light one, is needed for printing on paper. I don't know exactly about the CCD, but I'd think the situation is the same; if anything, an even lighter mask is needed.
Otherwise, the Zf looks beautiful, both inside and out.