Apple was the first to popularize the slide switch on smartphones to control notifications from ringing to vibrating or silent. For Android devices, OnePlus popularized it and OnePlus may have realized that the time has come for them to switch to additional physical buttons.
Digital Chat Station, a well-known leaker, shared that the slide switch on Oppo or OnePlus devices will be replaced with a new physical button. This button is said to be the Magic Cube Key which works like the Action Button on iPhone 15 and above. This Magic Cube Key is a button that can be pressed and held to control the notification sound or press to turn on the flashlight or launch other favorite apps.
At the moment it is still not known which devices will use this action button. It may be used on premium mid-range devices as an experiment first before being used on flagship devices. Let's wait and see.