The focus stacking (shift) feature on the Nikon D850 is a great feature.  To test it out, I set up some product shots using a light box and the Nikon 105mm macro lens.  In product photos below, the first photo is the first in a series of 11 shots using width 3.  The photos that include the manual are 33 shots.

The process is much simpler than I had imagined from reading other descriptions.  

You scroll to and open the Focus Shift Shooting option in the Photo Shooting Menu, choose the number of shots you want the camera to make, choose the width of each shot's focus, leave interval timer at 0, leave exposure smoothing off if exposure is constant, decide if you want photos stored in a separate folder (I did not for simplicity), turn Silent photography ON.  Then focus slightly in front of your subject, highlight Start and press OK.  The camera does the rest.

I used   https://www.heliconsoft.com/heliconsoft-products/helicon-focus/ to process the 11 or 33 images for each final shot.

The results are impressive - better than I could have done with a tilt/shift lens or a view camera with swings and tilts.

The first two photos are the setup.  I used a light box with built in leds from Amazon.   Cost - $26.

Give it a try.  Honestly, getting the lighting right was harder than using the focus stacking feature!

The SetupLightbox $26 at Amazon.

Focus Stacked Processed Image (11 shots) The first of the 11 shots Stacked First shot Stacked First shot Stacked First shot Stacked First shot Stacked First shot Stacked First shot Stacked First shot of 33 Stacked First shot of 33 Stacked First shot of 11 Stacked First shot of 11