Nikon Z9 Mirrorless Camera - Manual (Page 669)

669 A Custom Settings: Fine-Tuning Camera Settings
Choose how responsive the lens control ring is when assigned the
[
Aperture ], [ Power aperture ], [ Exposure compensation ], or [ ISO
sensitivity ] using Custom Setting f2 [ Custom controls (shooting) ] or
g2 [ Custom controls ].
f10: Control Ring Response
G button
U A Custom Settings menu