White balance:
The Auto white balance has three choices: Keep white, Keep overall atmosphere, Keep warm colors. The manual says that Keep white and Keep warm are related to incandescent lighting, but I think late day outdoor lighting is affected too?
Most of the time, I use either Auto--keep overall, or maybe the separate Natural Light Auto if I'm outdoors.
I think the Auto choices in White Balance and Picture Control are quite effective for most scenes.
I edit raw files from my raw + jpg Fine* pairs. The jpg is for occasional use and for reference of what I saw in the camera that day. So I don't normally pay close attention to the white balance and the picture control for my pairs.
I do like shooting in monochrome sometimes. It's very interesting to see the effects on B & W scenes with exposure changes, etc, right in the viewfinder. See the world in black & white!
Picture control:
Manual page:
picture controls
I see your Z5 ii allows selected standard picture controls to be removed from the display choices list. That's new, and very helpful. In my Z6 iii, there's a lot of annoying picture controls that I just scroll past.
To experiment with alternate picture controls, get the free
NX Studio software for your computer. You can select one of your downloaded raw files, and then
try every picture control with that raw file. The results are designed to match the camera's picture control outputs.
Custom picture controls:
NX Studio includes
Picture Control Utility 2, which used to be a separate download. See File --> Launch Picture Control Utility 2 in the menu. This is an easy way to make custom changes to the stock picture controls.
I edited a couple of monochrome picture controls to adjust the contrast, etc, as I liked. I added "-MOD" to the name, so I have MONOCHROME-MOD and GRAPHITE-MOD added in my camera. These get added to the end of the list, so I can scroll "left" from the Auto to wrap around to the end of the list, and my two monochrome mods.