One of the biggest problems encountered on iPhones with iOS 16.5; battery draining very fast. There are a lot of issues with iOS 16.5 that need fixing, such as the random disconnection of WiFi, the Apple weather app showing incorrect data, the Apple Lightning USB 3 camera adapter stopping working.
Earlier this month, Apple announced that 81% of all active iPhones have iOS 16 installed. The first beta of iOS 17 was released at WWDC last week for free for iPhone XS and newer models.