15 minutes maybe for an experienced technician but easily hours for someone who isn’t used to device repair which is not reasonable.
Source: iFixit iPhone 13 battery replacement
You’ve been duped if you honestly think devices can only reach IP68 resistance when they have sealed batteries.
My current phone has a headphone jack and removable sim card tray with removable storage that you can take out easily with your fingernail, and it’s IP68 and just as thin if not thinner than current gen iphones.
Lol, if you see a person wearing a tucked in blue polo shirt with dress pants with a yellow splotch on his shirt, you can probably make a safe assumption that they work for best buy :)