Nikon Z8 User Manual page 768

Delete Pictures from Both Slots
Choose whether deleting a copy of a picture recorded to both
memory cards with an option other than [Overflow] selected for
[Secondary slot function] in the photo shooting menu also deletes
the remaining copy.
Option
[Yes (confirmation
required)]
[Yes]
[No]
Before deleting one copy, you will be prompted to choose whether to delete
the other. To choose the option highlighted by default, press 2.
[Same pictures on w & x] is always selected; selecting [Yes] in the
confirmation dialog deletes both copies.
The confirmation dialog displayed is the same as that for pictures for which
no second copy exists. Deleting the current picture does not delete the copy.
G button U D playback menu
Description
694
Delete Pictures from Both Slots