HDR playback on iphone 15 pro

The iPhone 15 plus is now capable of increasing the screen peak brightness from 1000 nits to 1600 in HDR mode. I cannot see this happening. The screen brightness is on maximum. When i watch the same file over Infuse on Apple TV with 4K HDR television the difference is notable. I cannot find any setting in Infuse related to video playback on iPhone. I use the latest version of Infuse

It can depend on the actual file being played. Many HDR files are mastered with a max luminance of 1,000 nits, so playing these videos would not result in the phone going brighter than this.