A plausible report says that the iPhone 15 Pro will retain the iPhone 14 Pro maximum 27W charging power, despite rumors of it rising to 35W with Apple’s change to USB-C.
USB-C charging port on the iPhone 15 Pro (Source: Apple)
Those previous rumors about 35W were backed up by how Apple launched a 35W dual charger in 2022. Then, too, one of the expected benefits of switching to USB-C was a faster charging rate.