Barclays reports Apple product lines. iPhone 15 Pro Will use the volume up-down button, the Power button is a Solid State type, a button that is embedded or flat with the machine, not convex.
The iPhone 15 Pro may not have a side button.
The report comes from Cirrus Logic, one of Apple’s suppliers, who has revealed plans to manufacture and ship parts like the Tapic Engine for the iPhone 15 Pro.
The report reveals that the iPhone 15 Pro, 15 Pro Max will change the button on the side of the device that is pressed. to be smooth with the machine instead which will require parts of the Haptic Engine to be used instead of those buttons as well
The advantage of the Haptic button is that it reduces the gap between the device and the button. Makes the device more resistant to water and dust
In October, Ming-Chi Kuo also reported that the iPhone 15 Pro will use solid-sate volume and power buttons, along with the Tapic Engine, which when the user touches have Haptic Feedback Responsive, similar to the Home button on the iPhone 8, iPhone SE 2, SE 3.
source : https://www.macrumors.com/2022/11/23/iphone-15-pro-solid-state-buttons-hint/