There are, and always has been, waterproof devices with replaceable batteries. Phone manufacturers love that they can lie and say that a removable battery affects waterproofing. By making the battery hard to remove, and some other tricks, they make the phone less repairable. They then can convince consumers that they need to replace their phone every 18-24 months.
The only reason to replace your phone every two years is that you want the new shiny. All other reasons are artificial, marketing garbage created by manufactures who profit off of creating e-waste.