All the sensitivity settings from 5 to 10 have identical maximum turning speed. Instead of scaling max turning speed linearly as we expect sensitivity to do, the 5 through 10 settings function like a second aim acceleration slider.
Stick deadzones set to 0 don’t actually provide a 0% deadzone. There are still sizable deadzones that can’t be adjusted, regardless of your deadzone settings.
Maximum turning speed should allow for a 180 turn with a simple flick of the stick. Similar to how PC players can flick their wrist to do a 180. That’s only fair in a forced crossplay game.