When the hide the assistive ball on the full screen page is enabled, when the phone enters the full screen page, the assistive ball will be automatically hidden. You can check the position of the assistive ball by pulling down the control center.
Setting method
realme UI 6.0 & 5.0 & 4.0 & 3.0: Settings > System & updates/Additional Settings/System Settings > Assistive Ball > turn on Hide in full screen
realme UI 2.0 & 1.0: Settings > Convenience tools > Assistive Ball > turn on Hide in full screen
realme UI R & Go & S & T & U Edition: not supported