At the behest of the European Union, Apple had to change some of their iPhone designs. The first is to mandate the use of USB-C by 2024 and next in 2027 every smartphone must offer replaceable battery capabilities.
A recent Mark Gurman report stated that the iPhone 15 Pro will use a design that makes the device easier to repair. It is the same design on the iPhone 14 and iPhone 14 Plus which uses the screen panel and the back glass can be opened to access internal components easily so that repair work can be done faster.
This design is not used on the iPhone 14 Pro. This may be Apple's move to ensure that iPhones can be repaired by yourself at home through the Self Service Repair program. The program sells components and offers rental machines for users to repair devices at home.
Don't get me wrong, "easy to fix" here does not mean that first-time users can easily fix it themselves. But the repair method after this is not as complicated as other models which is only the screen panel that can be opened.